assignment for class 8 science chapter 2

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms Friend and Foe

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms Friend and Foe in English and Hindi Medium to Study Online or Download in PDF file format updated for new academic session 2024-25 following the latest CBSE Syllabus. Visit to NCERT Solutions main page to get all Subjects. The solutions are based on rationalised NCERT books published for 2024-25 exams.

Class 8 Science Chapter 2 NCERT Solutions

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NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe is given below. Video Format solution based on NCERT Solutions 2024-25 is also available. Download 8 Science App for offline use for new session.

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Important Terms on Class 8 Science Chapter 2

1. microorganisms.

This part of chapter 2 of Class 8 Science focuses a branch of microbiology which introduced the importance of microorganism in our ecosystem. We have seen several kinds of plants and animals . However, there are many living organisms around us which we cannot see with eyes alone. These are called microorganisms or microbes, such as bacteria, fungi, protozoa and some algae. For example, you might have observed that during rainy season moist bread gets to spoil and its surface gets covered with greyish-white patches.

2. Microorganisms and Diseases

Remember, water and soil are full of tiny organisms, but all of them not comes into microorganisms or microbe’s category. Do you know? Viruses are also microorganisms. They reproduce only inside the cells of the host organisms and cause serious disease like Polio, Chickenpox, Common cold. Diseases like Typhoid, Tuberculosis are bacterial diseases which are caused by protozoans.

3. Where do Microorganisms Live?

Microorganisms can survive under all types of environment, ranging from ice cold climate to hot springs and deserts to marshy lands. They are also found in polluted air and water as well as in inside the bodies of animals, including humans. Remember, microorganisms like amoeba can live alone while fungi and bacteria may live in colonies.

4. Microorganisms and Us

In this part of the content discusses the role of microorganisms, if microorganisms are good or bad for us. Thus, this part of the chapter will help, to an extent, in clearing this matter. As you know, that microorganisms play an essential role in our lives. Some of them are beneficial in many ways, whereas some others are harmful and causes diseases. They are used for various friendly purposes as they are used in cleaning up of the environment. For example, the organic wastes (vegetable peels, remains of animals, faeces etc.) are broken down into harmless and usable substance by bacteria, called manure. In agriculture, they are used to increase soil fertility by fixing nitrogen .

5. Microorganisms as a Friends

You may know that microorganisms are used for the preparation of curd, bread and cake. Curd contains several microorganisms. The bacterium Lactobacillus promotes the formation of curd. Similarly, yeast is also used in the baking industry for making slices of bread, pastries and cakes. Microorganisms are also used for the large-scale production of alcohol, wine and acetic acid. As yeast is used for the smell of alcohol as sugar converts into alcohol. The process of conversion of sugar into alcohol is called ‘fermentation’.

6. Microorganisms in Medicine

Whenever we fall ill, the doctor gives us some antibiotic tablets, capsule or injection. The sources of these medicines are microorganisms. Do you think why they are used? These medicines kill or stop the growth of the disease-causing microorganisms. Hence, such medicines are called ‘Antibiotics’. Antibiotics are even mixed with the feed of livestock and poultry to check microbial infection in animals. They are also used to control many plant diseases. When a disease-carrying microbe enters our body, the body produces ‘antibodies’ to fight the invader. In our childhood, we must have been given an injection for ‘Smallpox’ and ‘Polio’ to protect our-self against these diseases. Generally, these vaccines are made from microbes or microorganisms.

7. Microorganisms as Decomposer

As you learn before, some bacteria and blue-green algae are able to fix nitrogen from the atmosphere to enrich the soil with nitrogen and increase its fertility. You often see a large amount of dead organic matter in the form of decaying plants and dead animals on the ground. You find that they disappear after some time. This is because the microorganisms decompose dead organic waste of plants and animals, converting them into manure or nutrients. The other plants and animals again use these substances.

8. Harmful Microorganisms

This part of the Class 8 Science deals with some diseases which are caused by microorganisms. Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals, called ‘Pathogens’.

9. Disease – Causing Microorganisms in Humans

Microbial diseases that can spread from an infected person to a healthy person through the air, water, food or physical contact, called ‘Communicable Diseases’. When a person suffering from common cold sneezes, fine droplets of moisture carrying thousands of viruses are spread in the air, and then through the air, the virus enters the body of a healthy person while breathing. There are some insects and animals which act as ‘carriers’ of diseases causing microbes. Such as houseflies, mosquitoes, cockroach etc. Remember, ‘Anopheles Mosquito’ which careers the parasite of malaria. ‘Female Aedes’ mosquito act as a carrier of the dengue virus.

10. Disease – Causing Microorganisms in Animals and Plants

Anthrax is a dangerous human and cattle disease caused by the bacterium. Several microorganisms are there which causes diseases in plants like wheat, rice, potato, sugarcane, orange, apple and others. These diseases reduce the yield of crops. Microorganisms that grow on our food sometimes produce toxic substances. These make the food poisonous, causing severe illness and even death.

11. Food Preservation

In this part of the content gives an idea about food preservation from microorganism or microbes. As you know, spoilt food emits a bad smell and has a bad taste and change colour. So, it is very important that we preserve food to prevent it from being spoilt. Salt and edible oils are common chemicals generally used to check the growth of microorganisms, called ‘Preservatives’. Common salt has been used to preserve meat and fish for ages. Jams, jellies and squashes are preserved by sugar. As you know, boiling kills many microorganisms. You must have noticed that your mother is boiling milk before it is stored or used. Now in a day, dry fruits and even vegetables are sold in sealed airtight packets to prevent the attack of microbes.

12. Nitrogen Cycle

We know that our atmosphere has 78% nitrogen gas. Light and Nitrogen are the essential constituents of all living organisms as part of proteins, chlorophyll, nucleic acid and vitamins. Nitrogen cannot be taken by plants and animals directly. Certain bacteria and blue-green algae fix the nitrogen from the atmosphere and convert into compounds of nitrogen in the soil. When plants and animals die, bacteria and fungi convert the nitrogenous waste into nitrogenous compounds. And again, used by plants. As a result, the percentage of nitrogen in the atmosphere remains constant.

13. Nitrogen Fixation

As you know, the involvement of rhizobium bacteria in the fixation of nitrogen for leguminous plants. Rhizobium lives in the root nodules of leguminous plants and converts nitrogen into a soluble form for them. But that bacteria cannot make their own food. In return, leguminous plants provide food and shelter to the rhizobium bacteria. In this way, you can see microorganisms have tons of benefits, and they can cause deadly diseases too. As they are crucial in maintaining a balance in our ecological system, which helps to survive all living organisms.

Can microorganisms be seen with the naked eye? If not, how can they be seen?

No, microorganisms cannot be seen by naked eye as they are very small and are called microbes. They can be seen with the help of microscope.

What are the major groups of microorganisms?

Microorganisms are classified into four major groups are bacteria, fungi, protozoa and some algae.

Name the microorganisms which can fix atmospheric nitrogen in the soil.

Bacteria such as rhizobium and certain blue-green algae present in the soil can fix atmospheric nitrogen and convert into usable nitrogenous compounds, which are used by plants for the synthesis of plant proteins and other compounds.

What are antibiotics? What precautions must be taken while taking antibiotics?

The medicines that kill or stop the growth of the disease – causing microorganisms are called antibiotics. For example: Streptomycin, tetracycline, etc. Following precautions must be taken while taking antibiotics: Antibiotics should be taken only on the advice of a qualified doctor. One must finish the course prescribed by the doctor. Antibiotics must be avoided when not needed or in wrong doses.

Class 8 Science Chapter 2 MCQ with Answers

1. Which of the following reproduces only inside a host cell? (a) Bacteria (b) Virus (c) Amoeba (d) Fungus. 2. Paheli dug two pits, A and B, in her garden. In pit A, she put a polythene bag packed with some agricultural waste. In pit B, she dumped the same kind of waste but without packing it in a polythene bag. She, then covered both the pits with soil. What did she observe after a month? (a) Waste in pit A degraded faster than that in pit B. (b) Waste in pit B degraded faster than that in pit A. (c) Waste in both pits degraded almost equally. (d) Waste in both pits did not degrade at all. 3. A disease in human beings caused by virus is _______. (a) typhoid (b) influenza (c) dysentry (d) cholera 4. The two micro-organisms which live in symbiotic association in lichens are (a) fungus and protozoa (b) alga and bacteria (c) bacteria and protozoa (d) alga and fungus 5. The disease caused by a protozoan and spread by an insect is _________. (a) dengue (b) malaria (c) polio (d) measles 6. The gas released during the preparation of bread is (a) oxygen (b) carbon dioxide (c) nitrogen (d) sulphur dioxide 7. Pathogenic micro-organisms present in host cells are killed by medicines called (a) pain killer (b) antibodies (c) antibiotics (d) vaccines 8. Unscramble the jumbled words underlined in the following statements. (a) Cells of our body produce santiidobe to fight pathogens. (b) curbossulite is an air-borne disease caused by a bacterium. (c) Xanrhat is a dangerous bacterial disease. (d) Yeasts are used in the wine industry because of their property of meronettinaf.

1 (b) 2 (b) 3 (b) 4 (d) 5 (b) 6 (b) 7 (c) 8 (a) antibodies (b) tuberculosis (c) Anthra (d) fermentation

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NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend And Foe

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend And Foe are given below. Here we have provided the best and error-free answers to all the exercise questions that will strengthen your foundation in science. Solving NCERT questions will assist you in grasping the content in the Crop Production and Management chapter in a better way.

In these solutions, we have answered all the intext and exercise questions provided in NCERT class 8 science textbook.  NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend And Foe provided in this article are strictly based on the CBSE syllabus and curriculum. Students can easily download these solutions in PDF format for free or can read them online.

Microorganisms: Friend And Foe Class 8 Science NCERT Solutions

Exercise Questions

Question 1: Fill in the blanks:

(a) Microorganisms can be seen with the help of a _______. (b) Blue green algae fix _______ directly from air to enhance fertility of soil. (c) Alcohol is produced with the help of _______. (d) Cholera is caused by ________.

(a) Microorganisms can be seen with the help of a microscope.

(b) Blue green algae fix nitrogen directly from air to enhance fertility of soil.

(c) Alcohol is produced with the help of microorganisms.

(d) Cholera is caused by bacteria.

Question 2: Tick the correct answer:

(a) Yeast is used in the production of

(i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen

Answer: (ii) Alcohol

(b) The following is an antibiotic

(i) Sodium bicarbonate (ii) Streptomycin (iii) Alcohol (iv) Yeast

Answer: (ii) Streptomycin

(c) Carrier of malaria-causing protozoan is

(i) female Anopheles mosquito (ii) cockroach (iii) housefly (iv) butterfly

Answer: (i) Female Anopheles mosquito

(d) The most common carrier of communicable diseases is

(i) ant (ii) housefly (iii) dragonfly (iv) spider

Answer: (ii) Housefly

(e) The bread or idli dough rises because of

(i) heat (ii) grinding (iii) growth of yeast cells (iv) kneading

Answer: (iii) Growth of yeast cells

(f) The process of conversion of sugar into alcohol is called

(i) nitrogen fixation (ii) moulding (iii) fermentation (iv) infection

Answer: (iii) Fermentation

Question 3: Match the organisms in Column A with their action in Column B.

Question 4: Can microorganisms be seen with the naked eye? If not, how can they be seen?

Answer: No, microorganisms cannot be seen by naked eye as they are very small and are called microbes. They can be seen with the help of microscope.

Question 5: What are the major groups of microorganisms?

Answer: Microorganisms are classified into four major groups are bacteria, fungi, protozoa and some algae.

Question 6: Name the microorganisms which can fix atmospheric nitrogen in the soil.

Answer: Bacteria such as rhizobium and certain blue-green algae present in the soil can fix atmospheric nitrogen and convert into usable nitrogenous compounds, which are used by plants for the synthesis of plant proteins and other compounds.

Question 7: Write 10 lines on the usefulness of microorganisms in our lives.

Answer: Microorganisms are too small to be seen through naked eyes. However, they are vital to plants and the environment.

Importance of microorganisms:

• They are used in winemaking, baking, pickling and other food-making processes.
• Alcoholic fermentation by yeast is widely used in the preparation of wine and bread.
• A bacterium Lactobacillus promotes the formation of curd.
• Microbes are used to reduce pollution.
• They are used to increase soil fertility by fixing atmospheric nitrogen.
• Microbes are also useful in preparing many medicines and antibiotics.
• Certain microbes are also used in the biological treatment of sewage and industrial effluents.

Question 8: Write a short paragraph on the harms caused by microorganisms.

Answer: Harmful effects of micro-organisms:

Micro-organisms cause diseases in animals. For example, in humans, bacteria cause diseases such as tuberculosis, cholera, typhoid, etc. In cattle, the foot and mouth disease is caused by a virus. Also, several microbes cause diseases in plants. For example, the productivity of wheat, orange, apple, etc. is reduced due to microbial diseases in plants. Certain microbes, on entering into our body, produce toxic substances. This leads to food poisoning. Some micro-organisms such as fungus spoil our food. For example, bread when left unused under moist conditions gets spoilt by fungus, producing a white cotton-like growth on the bread.

Question 9: What are antibiotics? What precautions must be taken while taking antibiotics?

Answer: The medicines that kill or stop the growth of the disease-causing microorganisms are called antibiotics. For example: Streptomycin, tetracycline, etc.

Following precautions must be taken while taking antibiotics:

• Antibiotics should be taken only on the advice of a qualified doctor.
• One must finish the course prescribed by the doctor.
• Antibiotics must be avoided when not needed or in wrong doses.

CBSE Class 8 NCERT solutions Science Chapter 2 PDF

Below we have listed the topics discussed in NCERT Solutions for Class 8 Science Chapter 2. The list gives you a quick look at the different topics and subtopics of this chapter.

NCERT Solutions for Class 8 Science Chapter 2 – A Brief Discussion

CBSE Class 8 Science NCERT Solutions Chapter 2 helps students to clear their doubts and to score good marks in the board exam. All the questions are solved by experts with a detailed explanation that will help students complete their assignments & homework. Having a good grasp over CBSE NCERT Solutions for Class 8 Science will further help the students in their preparation for board exams and other competitive exams such as NTSE, Olympiad, etc.

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NCERT Solutions for Class 8 Science Chapter 2 Free PDF Download

Ncert solutions for class 8 science chapter 2 – microorganisms.

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CBSE Class 8 Science Chapter 2 – Microorganisms NCERT Solutions

NCERT Solutions for Class 8 Science Chapter 2 deals with Microorganisms. First of all, a microorganism refers to a microscopic organism. This chapter involves useful and harmful types of microbes. Furthermore, this chapter also covers the habitat of Microorganisms. The chapter is full of colorful diagrams and images. The chapter also has information on the life cycle of Microorganisms. There is also a part of the contribution of these organisms.

Sub-topics covered under NCERT Solutions for Class 8 Science Chapter 2

• 2.1 Microorganisms
• 2.2 Where do Microorganisms Live?
• 2.3 Microorganisms and Us
• 2.4 Harmful Microorganisms
• 2.5 Food Preservation
• 2.6 Nitrogen Fixation
• 2.7 Nitrogen cycle

NCERT Solutions for Class 8 Science Chapter 2

This is a very important chapter in Science. Students here will certainly learn about the harms of Microorganisms. Therefore, students will take safety measures. So, this chapter will help to make students more aware of the danger. Furthermore, the chapter teaches how these microbes can be useful. This chapter is essential for medicine. This is because medicines make use of Microorganisms. Also, students will learn how microbes are useful in food preservation.

Below is a brief explanation of the sub-units of chapter 2

2.1 Microorganisms – A Microorganism is a very small organism. Most noteworthy, no one sees it with the naked eye. This is due to their extremely tiny size.

2.2 Where do Microorganisms Live? – Microorganisms can survive in all types of environment. Furthermore, Microorganisms also exist inside the bodies of animals. Some of them live alone while others live in colonies. Hence, they can live anywhere.

2.3 Microorganisms and Us – Microorganisms influence Human lives. Some are good for humans while others are bad. Hence, there exist friendly and harmful microbes.

2.4 Harmful Microorganisms – Harmful microbes can cause disease. Furthermore, they can cause disease to humans, plants, and animals.

2.5 Food Preservation – Microbes certainly help to preserve food. This sub-unit deals with it.

2.6 Nitrogen Fixation – This means some Microorganisms fix nitrogen. The part certainly has more information on that.

2.7 Nitrogen cycle – Microorganisms fix nitrogen from the atmosphere. After that, they convert that into compounds of nitrogen. Then plants can use these compounds from the soil. When plants and animals die they turn into nitrogenous wastes. Consequently, the microbes convert these wastes into compounds.

You can download NCERT Solutions for Class 8 Science Chapter 2 PDF by clicking on the button below

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Living Science 2019 Solutions for Class 8 Science Chapter 2 - Microorganisms

• textbook solutions
• Microorganisms

Living Science 2019 Solutions for Class 8 Science Chapter 2 Microorganisms are provided here with simple step-by-step explanations. These solutions for Microorganisms are extremely popular among class 8 students for Science Microorganisms Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science 2019 Book of class 8 Science Chapter 2 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science 2019 Solutions. All Living Science 2019 Solutions for class 8 Science are prepared by experts and are 100% accurate.

Page No 26:

Question 1:.

All microbes are harmful. Do you agree? Give reasons.

Not all microbes are harmful. Some of the microbes produce antibiotics which is used for the treatment of many diseases. Moreover, certain microbes such as Yeast are used for food production. Thus, all microbes are not harmful.

Question 2:

Name the types of microorganism that: a. have chlorophyll:_________          b. do not have a cellular structure:___________

a. Algae are microorganisms that contain chlorophyll. b. Viruses do not have a cellular structure.

Question 3:

Give one property because of which viruses are regarded as being on the borderline of living and non−living.

Viruses do not reproduce outside their host cell. However, when viruses enter into living cells, they are able to reproduce. This ability of viruses to selectively reproduce within the host cell allows viruses to behave as living as well as non-living organisms.

Question 4:

Which of these are closer to plants−algae or protozoa? In what aspect?

Algae are more closely related to plants. This is because both plants and algae possess chlorophyll and have the ability to produce their food by the process of photosynthesis. Protozoa, on the other hand, are more related to animals.

Question 5:

Where do you normally expect to find algae−in the soil, in a pond or in the air?

Algae are primarily found in the aquatic environments such as lakes, ponds and seawater.

Page No 31:

While making cake or dhokla, the dough rises because of a substance that is produced during fermentation. What substance is this? Why does it cause the dough to rise?

During the preparation of dhokla or cake, the fermentation process releases carbon dioxide gas, which causes the dough to rise. The carbon dioxide gas is released in the form of bubbles. This causes the dough to rise.

To prevent a disease caused by a certain microbe, doctors inject the same microbes in a person's blood. How is it ensured that this prevents the disease instead of causing it? What is this process of injecting microbes called?

The microbes that are injected in a person's blood to treat a disease are either killed or weakened prior to their administration. This ensures that the microbe do not cause any harmful effects in the body. The process of injecting microbes in the body to prevent diseases is called vaccination or immunization.

Microbes that live inside the bodies of animals normally cause diseases. However some of them also help animals. Give an example to prove this point

In digestive system of certain herbivorous animals such as goats and cows, houses certain beneficial protozoa and bacteria. These microbes help herbivorous to digest plant materials by breaking down cellulose.

Pasteurization means boiling the milk to kill germs. Do you agree? Give reasons.

Pasteurization is a food preservation technique, in which the milk is firstly heated to a temperature of 70ºC. Afterwards, the milk is rapidly cooled down to prevent the growth of microbes. Thus, pasteurization is not just boiling the milk to get rid of germs.

Page No 33:

Which of the following cannot be classified as either living or non-living? (a) fungi (b) bacteria (c) viruses (d) protozoa

(c) viruses Viruses have the characteristics of both living and non-living organisms. Therefore, they cannot be classified as either living or non-living.

Amoeba is a (a) bacterium. (b) virus. (c) fungus. (d) protozoa.

(d) protozoa Amoeba is a unicellular organism which has animal-like characteristics. Thus, it is grouped under protozoa.

Which of the following make their own food by photosynthesis? (a) algae (b) viruses (c) fungi (d) protozoa

(a) algae Algae have chlorophyll in them. So, they can make their own food by photosynthesis.

The unicellular organisms that sour milk to make curd are (a) bacteria. (b) viruses. (c) fungi. (d) protozoa.

(a) bacteria A bacterium known as lactobacillus converts milk into curd and make it sour.

Which of the following is responsible for making bread soft and fluffy? (a) finely ground flour (b) sugar (c) alcohol given off during fermentation of sugar (d) carbon dioxide gas given off during fermentation of sugar

(d) carbon dioxide gas given off during fermentation of sugar Carbon dioxide gas escapes during baking and a free space is formed in the bread. Thus, the bread becomes soft and fluffy.

Question 6:

Which of these do not have a regular cell structure? (a) bacteria (b) viruses (c) algae (d) protozoa

(b) viruses Bacteria, algae and protozoa have a regular cell structure but viruses lack it.

Question 7:

Which of these are found as both unicellular and multicellular organisms? (a) bacteria (b) viruses (c) algae (d) protozoa

(c) algae Algae are found as both unicellular and multicellular organisms.

Question 8:

The bacterium Lactobacillus is useful in making (a) cheese. (b) cake. (c) alcohol. (d) all of these

(a) cheese The bacterium known as Lactobacillus is useful in making cheese, whereas cake and alcohol are made with the help of yeast, which is a fungus.

Question 9:

Microorganisms spread through (a) air. (b) cuts. (c) water. (d) all of these

(d) all of these Microorganisms are found everywhere in the environment and they spread through air, cuts and water.

Question 10:

Which of these does not prevent growth of bacteria? (a) salt (b) sugar (c) water (d) oil

(c) water Salt, sugar and oil are used as preservatives for food and they prevent the growth of bacteria. However, water acts as a medium for bacterial growth.

What is the study of microorganisms known as?

The study of microorganisms is known as microbiology.

Microbes are disease-causing microorganisms. True or false?

False. Disease-causing microorganisms are known as pathogens or germs.

All fungi are unicellular. True or false?

False. Some fungi are multicellular. Example of a multicellular fungus is bread mould.

Page No 34:

Under unfavourable conditions, microorganisms form a __________ around themselves.

Under unfavourable conditions, microorganisms form a cyst around themselves.

What are spherical bacteria called?

Spherical bacteria are called cocci.

A virus can reproduce on its own. True or false?

False. A virus needs to enter a living cell to reproduce.

Where are algae mostly found−in water or on land?

Algae are mostly found in water bodies like ponds, lakes, rivers and seas.

Is the decomposition of the bodies of dead plants and animals by microorganisms desirable or undesirable?

The decomposition of dead plants and animals by microorganisms is desirable as it helps in recycling nutrients.

Name the class of medicines usually made from fungi or bacteria that can cure dangerous diseases.

Antibiotics is the class of medicines usually made from fungi or bacteria. Antibiotics can cure dangerous diseases.

Is yeast a bacterium or a fungus?

Yeast is a fungus.

Question 11:

The female Aedes mosquito is a carrier of the ________ virus.

The female Aedes mosquito is a carrier of the dengue virus.

Question 12:

The foot and mouth disease is caused by a __________

The foot and mouth disease is caused by a virus .

Question 13:

Food poisoning is caused by a toxin getting accidentally mixed with food. True or false?

True. When microorganisms like fungi or bacteria that produce toxins, sometimes grow on food, due to which food gets spoilt. If such spoilt food is consumed, it may cause food poisoning.

Question 14:

What is heating milk to a high remperature and then cooling it quickly called?

The process of heating milk to a high temperature and then cooling it quickly is called pasteurisation.

Question 15:

Salt forces microbes to lose water. True or false?

True. When salt is added to a food substance for its preservation, it forces the microorganisms to lose water by the process of osmosis.

What is a microorganism?

A microorganism is a tiny organism which can only be seen through a microscope. Example: bacteria, virus, protozoa, algae and fungi.

Name the five groups into which microorganisms are divided. Which of these have only unicellular organisms?

The five groups into which microorganisms are divided are bacteria, virus, protozoa, algae and fungi. Bacteria and protozoa have only unicellular organisms.

The three types of bacteria shown in this figure are: a) cocci b) bacilli c) spirilla

What kind of living organisms are classified as algae? Give two examples.

Simple plant-like organisms that have cell walls and chlorophyll are classified as algae. They lack roots, stems or leaves, but are able to make their own food through the process of photosynthesis. Two examples of algae are Spirogyra and Fucus .

Under what circumstances can viruses reproduce?

Viruses can reproduce only when they are inside the living cell of an organism. They multiply with the help of resources from the host cell.

Give one important use of algae.

Algae produce oxygen during photosynthesis that animals and humans use during respiration.

How does cooling help in food preservation?

Cooling helps in food preservation as microorganisms are not able to grow and reproduce at lower temperatures. Thus, food is preserved and microbial growth is prevented.

What causes food poisoning?

Microorganisms grow on food substances and produce toxins, turning food poisonous. Such spoilt food, when consumed, causes food poisoning.

What is pasteurization?

Heating milk to a high temperature of 70 degree celcius for about 30 seconds and then cooling it quickly is known as pasteurisation. This method kills most of the bacteria present in the milk and preserves it.

How does mosquito help in spreading viruses/microorganisms?

Mosquitoes such as female Anopheles and Aedes are carriers of germs that cause malaria and dengue fever, respectively. When these mosquitoes bite a healthy person, they inject the germs into his body. Thus mosquitoes spread viruses and other disease-causing microorganisms.

Microorganisms are found even in places where no other life forms can exist. What makes microorganisms so hardy?

Microorganisms are found even in places where no other life forms can exist. They form a hard outer covering called a cyst around themselves that makes them hardy. Under unfavourable circumstances, they survive by remaining inside the cyst in an inactive form.

Which microorganism is used to make bread soft and fluffy? Discuss how this happens.

Yeast is used to make bread soft and fluffy. When yeast is mixed with the flour for making bread, it breaks down sugar and produces alcohol and carbon dioxide gas. When the bread is being baked, carbon dioxide gas escapes due to the heat, causing the bread to become soft and fluffy.

What is fermentation? Discuss its use in making alcoholic beverages.

The conversion of sugar into alcohol by yeast is known as fermentation. This process is used in the preparation of alcoholic beverages like beer and wine. Beer is produced by the fermentation of sugar in germinating barley and wine is prepared by fermentation of sugar in grapes.

How do viruses cause diseases?

A virus enters the living cell of an organism and uses the resources inside the host cell for its reproduction. It duplicates itself and then the host cell dies and finally bursts. The newly formed virus released from that cell starts invading the other cells. This process is repeated and in this way, many cells of the host organism are destroyed. As large numbers of host cells are destroyed, the person becomes ill.

How does a vaccine work?

Vaccines are produced from dead or weakened microorganisms such as bacteria or a virus. When vaccines are administered to a person, his body produces antibodies which fight against pathogens. These antibodies remain inside the body and provide protection from any future attack by that particular microorganism.

How does salt prevent food spoilage?

When salt is added to food, it forces the microorganisms to lose water by the process of osmosis. Thus, microorganisms are not able to grow in the food. In this way, salt prevents food spoilage.

What is 'dehydration' of food? In what way is this technique useful?

Dehydration of food means the removal of water from food. It is done by drying the food. Water is a medium required for the growth of microorganisms. Thus, this technique is useful as it stops the growth of microorganisms in the food.

Which microorganisms act as decomposers? How is this activity useful to us?

Bacteria, protozoa and fungi act as decomposers. These decomposers break down organic matter present in the bodies of dead plants and animals into simple substances and mix them in the soil. A plant growing in this soil absorbs the nutrients and passes them to the animals that consume the plant products. Thus, these microorganisms act as decomposers and help in recycling the nutrients in the soil.

Page No 35:

Why are viruses considered to be on the borderline of the living and non-living?

Viruses do not grow or reproduce by themselves, which makes them non-living. However, when a virus enters the living cell of an organism, it makes use of the resources in the host cell and starts reproducing. This makes viruses living, as reproduction is an important characteristic of a living organism. Due to this, viruses are considered to be on the borderline of the living and non-living.

Discuss three important ways in which bacteria are useful to us and two ways in which they are harmful.

The three important ways in which bacteria are useful to us are: 1) Formation of curd: When a small amount of curd (known as starter) is added to milk, the bacteria known as Lactobacillus , convert the milk into curd. 2) Nitrogen fixation: The bacteria known as Rhizobium live in the root nodules of leguminous plants. These bacteria fix the atmospheric nitrogen and converts it into nitrates that can be used by the plants. 3) Retting of jute: Bacteria help in separating jute fibres from the rest of the tissues of the jute plant. These fibres are used in making various articles. Two ways in which bacteria are harmful to us are: 1) Diseases: Bacteria cause many diseases in humans like cholera and typhoid. 2) Food spoilage: Bacteria spoil food. Examples: putrefaction of meat and rotting of fruits and vegetables.

Discuss the different ways in which communicable diseases spread from person to person.

Communicable diseases spread from one person to another through various means. These are: 1) Through air: When a person suffering from cold or flu sneezes or coughs, germs are released that spread through the air. 2) Through contaminated food and water: When houseflies sit on garbage, germs stick to their bodies. When these houseflies sit on uncovered food or water, they contaminate the food or water by transferring the germs. 3) Through mosquitoes: Mosquitoes such as the female Aedes carry germs that cause dengue fever. 4) Through cuts and wounds: Microbes also enter our body through cuts or wounds. 5) Through direct contact: Diseases such as chickenpox can spread through direct contact from an infected person.

Discuss five methods of food preservation.

The following are the five methods of food preservation: 1) Heating: When food is heated at high temperature, all the microorganisms present in it are destroyed. 2) Pasteurisation: In this method, milk is heated at a high temperature for 30 seconds and then quickly cooled. This process kills the microorganisms present in milk. 3) Cooling: It prevents the growth and reproduction of microorganisms because microorganisms are not able to reproduce at low temperatures. 4) Drying: This process removes water from food. Since, microorganisms need water for their growth, drying food prevents the growth of microorganisms. 5) Canning: In this method, food is sterilised and then canned in airtight containers. This prevents the growth of microorganisms.

Why do you think: (a) curd sets faster in summer than in winter? (b) curd turns sour faster in summer than in winter?

(a) Bacteria grow faster in summer, as they require warm temperatures to grow. Thus, they set curd faster in summer than in winter. (b) Curd turns sour faster in summer than in winter because during summer, the temperature is high, which allows the bacteria to grow and multiply faster.

The sealed packets in which food items such as chips are sold are usually filled with nitrogen. How do you think that helps?

The sealed packets in which food items such as chips are sold are usually filled with nitrogen as nitrogen prevents the growth of microorganisms. Microorganisms need oxygen for their growth and survival. Nitrogen replaces all the oxygen in the packets, thus preventing the growth of microorganisms. In this way, the food items are prevented from being spoilt by microorganisms.

Why should you always wash your hands before handling food and after coming from the toilet?

We should always wash our hands before handling food and after using the toilet to remove the germs from our hands. If we eat food without washing our hands, there is a chance that the germs may enter our body, causing infections.

Evolution i.e. changes in an organism to adjust to the environment, as suggested by Charles Darwin, is a very slow process that takes place over tens of thousands of generations, over millions of years. However, in bacteria, development of resistance to antibiotics, which is a type of evolution, takes place within our own lifetime. Can you say why it occurs so quickly in bacteria?

Evolution occurs quickly in bacteria, as bacteria reproduce faster than other organisms. Some bacteria may reproduce as fast as every 20 minutes, which is half-a-million times faster than humans. This is the reason why bacteria become resistant to antibiotics within our own life time.

Ancient Egyptians applied mouldy bread on infected cuts and wounds to heal them. Why do you think this helped in healing the wounds? Nowadays we do not use mouldy bread to cure infection. What do we use instead?

We are aware that some of the moulds or fungi are used to produce antibiotics. Antibiotics are chemicals which kill or stop the growth of disease causing microbes. Although, the ancient Egyptians were not aware of the concept of antibiotics but they were well aware about the wound healing properties of these moulds. These chemicals produced by the moulds helped in the healing of wounds by restricting the growth of microorganisms or by killing them. Nowadays, we can culture these fungi and extract antibiotics from them or we can synthesise the antibiotics artificially.

View NCERT Solutions for all chapters of Class 8

NCERT Solutions for Class 8 Science | CBSE Class 8th Science Solutions for All Chapters

NCERT Solutions of Class 8th Science is an extremely helpful resource for students in Class 8. Students can use the  NCERT Solutions for Class 8 Science during their exam preparation and resolve their doubts easily. Our Class 8 Science NCERT Textbook Solutions helps you to understand the concepts in a better way. You can download these NCERT Solutions for free and prepare Notes on your own and quickly revise the syllabus whenever needed.

Class 8 Science NCERT Solutions | NCERT Solutions of Class 8 Science PDF Download

Ncert class 8 science solutions chapters brief, tips for clearing cbse class 8 science exam.

• Are NCERT Science Books good for Class 8 CBSE Students?
• Where do I get Class 8th Science NCERT Solutions for All Chapters?
• How to download Class 8 Chapter Wise Science Solutions PDF?

If you are having any trouble understanding the topics of Class 8 Science you can check from our CBSE Class 8th Science NCERT Solutions as they are prepared as per the latest syllabus guidelines. CBSE Class 8 Science Solutions PDF for all Chapters can be accessed and downloaded for free so that you can use them anywhere and anytime.

Our Class 8th NCERT Solutions for Science present here covers questions from NCERT Solutions, Textbook Exercises, Exemplar Problems, Worksheets, and MCQ Questions for 8 Class Science . You will not have any difficulty in understanding the concepts as all of them are thoroughly explained using simple language. Just tap on the quick links and use them at your convenience.

NCERT Solutions for Class 8th Science

Chapter 1 Crop Production and Management

• Chapter 2 Microorganisms: Friend and Foe

Chapter 3 Synthetic Fibres and Plastics

• Chapter 4 Materials: Metals and Non-Metals

Chapter 5 Coal and Petroleum

Chapter 6 combustion and flame, chapter 7 conservation of plants and animals.

• Chapter 8 Cell – Structure and Functions

Chapter 9 Reproduction in Animals

Chapter 10 reaching the age of adolescence, chapter 11 force and pressure, chapter 12 friction, chapter 13 sound, chapter 14 chemical effects of electric current, chapter 15 some natural phenomena, chapter 16 light.

• Chapter 17 Stars and The Solar System

Chapter 18 Pollution of Air and Water

We have mentioned the NCERT Science Solutions of Class 8 All Chapters so that you will have a glimpse of topics present in them. Refer to them and learn what is the syllabus to be covered during your preparation in order to score well in your exams. They are as under

Chapter 1 is included in the syllabus to let students know how food is being produced using various agricultural practices. It also includes information on how crops are being categorized on basis of seasons such as rabi and Kharif. In addition, you will learn about the traditional and modern practices of agriculture.

Chapter 2 Micro-Organisms Friend and Foe

NCERT Class 8 Science Chapter 2 begins with the introduction to microorganism like its definition, How it plays an important role in our lives considering few examples like use of microorganisms in curd making, medicines, and vaccine. It even includes information on how harmful microorganisms can be in food at times and leads to food poisoning.

In Chapter 3 Synthetic Fibres and Plastics you will deal with types of synthetic fibers such as Rayon, Nylon, Polyester, and Acrylic. Furthermore, you will get acquainted with the characteristics of synthetic fibers, introduces to plastic, and their effect on the environment.

Chapter 4 Materials Metals and Non- Metals

NCERT Class 8th Science Chapter 4 explains the physical and chemical properties of metals and non-metals. To explain the properties in a better way they also took few activities in the NCERT Books. The chapter even describes the uses of metals and non-metals.

Ch 5 of Science Books explains the natural resources and their classification. It explains coal, petroleum and natural gas are the fossil fuels formed from the dead remains of living organisms millions of years ago. You will also come across how coal gas, coke, and coal tar are formed using the coal, refining of petroleum. This Chapter on Coal and Petroleum brings awareness among students that natural resources are limited and should be used wisely.

Students of Class 8 will learn about different types of Combustion in this chapter with beautifully explained activities. Here you will know the concept of flame, measures on how to control the fire, fuel efficiency and harmful effects of burning the fuel, etc.

Chapter 7 lays emphasis on deforestation and causes for it, consequences we need to face as a result of deforestation, ways on how to preserve wildlife and forests. It further discusses Biosphere reserve, endemic species, flora and fauna, wildlife sanctuary, red data book, national park, migration, recycling of paper.

Chapter 8 Cell Structure and Functions

This chapter explains that the cell is the smallest living part of an organism. A cell can take various sizes and shapes, and how a number of cells vary from organism to organism, etc.  NCERT Science Class 8 Ch 8 further briefs on parts of cells in detail, compares plants and animals cells.

Students will become familiar with the two modes of reproduction in Animals such as Sexual and Asexual Reproduction. They can learn Sexual Reproduction in detail such as male reproductive organs, female reproductive organs, fertilization, embryo development, viviparous and oviparous animal. Asexual Reproduction is also covered in detail here.

In Chapter 10 Students will know the role of hormones in the human body that change a child into an adult. It further explains the topics of Adolescence and Puberty. Topics like secondary sexual characters, reproductive phase of life in humans, the role of hormones in initiating reproductive function, sex determination, other hormones except for sex hormones, reproductive health are explained in detail.

A lot of activities are given to make the chapter interesting. You will get to know how force arises with the interaction of two objects, type of force be it pull or push, and how it can transform the shape of an object. Furthermore, the concepts such as contact and non-contact forces, pressure, the pressure exerted by both liquids and gases, atmospheric pressure are covered in detail.

NCERT Class 8 Science explains the concepts such as friction, factors affecting it, and how friction can be increased or reduced. The Chapter Friction further explains the topic of fluid friction clearly.

Sound plays a crucial role in human lives and helps in communicating with one another. Chapter 13 explains clearly how sound is produced and how it travels and how we can hear sound and why certain sounds are louder.

In Ch 14 you will know how some liquids act as a good conductor for electricity, why certain liquids are a poor conductors for electricity. In addition, you will learn the concepts of electroplating, the chemical effects of electric current, etc.

In Chapter 15 students will get acquainted with lighting and earthquakes. In addition, you will learn the ways on how to minimize the destruction from these natural phenomena. This Chapter is introduced so that students will be aware of natural phenomena and protect themselves from such scenarios.

This chapter tells us about the light we are able to see around us. It even illustrates the concepts of the law of reflection, multiple reflections, regular and diffused reflection. Sunlight is also known as white light consists of 7 colors and the splitting of light is known as dispersion. The Chapter also describes how we should take care of our eyes.

Chapter 17 Stars and the Solar System

NCERT Book for Class 8 Science Chapter 17 talks about celestial objects, moon, stars, and constellations. Solar System is described along with features of each planet present in it. Other Members of the Solar System such as Comets, Asteroids, Meteors, Meteorites, Artificial Satellites are explained here.

Ch 18 Pollution of Air and Water helps us to be aware of harmful changes that occur in our surroundings due to pollution and its effect on human lives. It starts with air pollution and how air is getting polluted. Furthermore, you will know the concept of the greenhouse effect and methods for reducing air pollution. It also describes water pollution and methods for purifying water.

Go through the simple tips and keep them in mind to clear the Class 8 Science Exam with ease. They are as follows

• Be aware of the CBSE Class 8 Syllabus beforehand itself.
• Know the Exam Pattern Trends, Kind of Questions appearing in the exam, etc.
• Study on a regular basis and resolve all your queries.
• Break the bigger concepts into small chunks and test your understanding of each topic.
• Before you write the test give yourself some time and keep your mind fresh.

FAQs on Science NCERT Solutions for Class 8

1. Are NCERT Science Books good for Class 8 CBSE Students?

Yes, NCERT Science Books can be great for a student of Class 8 as they explain all the Chapters of the Class 8 Syllabus in a simple language. They can complement one’s learning to clear the CBSE Board Exams.

2. Where do I get Class 8th Science NCERT Solutions for All Chapters?

You can get NCERT Solutions for Class 8 Science All Chapters organized efficiently on our page.

3. How to download Class 8 Chapter Wise Science Solutions PDF?

You can download Chapter Wise Class 8 Science NCERT Solutions PDF by simply tapping on the quick links available.

Wrapping Up

If you like the article on NCERT Solutions for Class 8 Science do share it with your friends and family who are preparing for CBSE Class 8 Exams or any Other Competitive Exams. For any suggestions do contact us via the comment section so that we can get back to you. Keep in touch with us to avail latest updates on NCERT Books, Solutions, Previous Papers, etc.

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NCERT and CBSE Solutions for free

Class 8 Science Assignments

We have provided below free printable Class 8 Science Assignments for Download in PDF. The Assignments have been designed based on the latest NCERT Book for Class 8 Science . These Assignments for Grade 8 Science cover all important topics which can come in your standard 8 tests and examinations. Free printable Assignments for CBSE Class 8 Science , school and class assignments, and practice test papers have been designed by our highly experienced class 8 faculty. You can free download CBSE NCERT printable Assignments for Science Class 8 with solutions and answers. All Assignments and test sheets have been prepared by expert teachers as per the latest Syllabus in Science Class 8. Students can click on the links below and download all Pdf Assignments for Science class 8 for free. All latest Kendriya Vidyalaya Class 8 Science Assignments with Answers and test papers are given below.

Science Class 8 Assignments Pdf Download

We have provided below the biggest collection of free CBSE NCERT KVS Assignments for Class 8 Science . Students and teachers can download and save all free Science assignments in Pdf for grade 8th. Our expert faculty have covered Class 8 important questions and answers for Science as per the latest syllabus for the current academic year. All test papers and question banks for Class 8 Science and CBSE Assignments for Science Class 8 will be really helpful for standard 8th students to prepare for the class tests and school examinations. Class 8th students can easily free download in Pdf all printable practice worksheets given below.

Topicwise Assignments for Class 8 Science Download in Pdf

Advantages of Class 8 Science Assignments

• As we have the best and largest collection of Science assignments for Grade 8, you will be able to easily get full list of solved important questions which can come in your examinations.
• Students will be able to go through all important and critical topics given in your CBSE Science textbooks for Class 8 .
• All Science assignments for Class 8 have been designed with answers. Students should solve them yourself and then compare with the solutions provided by us.
• Class 8 Students studying in per CBSE, NCERT and KVS schools will be able to free download all Science chapter wise worksheets and assignments for free in Pdf
• Class 8 Science question bank will help to improve subject understanding which will help to get better rank in exams

Frequently Asked Questions by Class 8 Science students

At https://www.cbsencertsolutions.com, we have provided the biggest database of free assignments for Science Class 8 which you can download in Pdf

We provide here Standard 8 Science chapter-wise assignments which can be easily downloaded in Pdf format for free.

You can click on the links above and get assignments for Science in Grade 8, all topic-wise question banks with solutions have been provided here. You can click on the links to download in Pdf.

We have provided here topic-wise Science Grade 8 question banks, revision notes and questions for all difficult topics, and other study material.

We have provided the best collection of question bank and practice tests for Class 8 for all subjects. You can download them all and use them offline without the internet.

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NCERT Solutions for Class 8 Science - Free PDF Download

Science is a fascinating subject. The vast universe we live in is brimming with objects that exemplify innumerable scientific principles. Today's children are growing up in a more technologically and scientifically advanced world than ever before. As a result, people must acquire sophisticated and fundamental scientific procedures in order to live a stress-free existence. Children who are scientifically literate take Science as a subject at school and use it to guide their career choices. Teaching Science to Class 8 pupils can be challenging for teachers since the terminology used in the textbook has a variety of scientific words that are unfamiliar to kids. This has an impact on pupils' preparation for their Class 8 examinations. They grow quite worried about the questions from the Science textbook by the end of each chapter.

Students may use NCERT Solutions for Class 8 Science to find all of the solutions to problems from the textbook chapters. The NCERT Solutions for Class 8 provide solutions to questions from the NCERT Science Class 8 textbook's Physics, Chemistry, and Biology sections . The written answers are highly thorough and detailed, removing any concerns about the hard scientific issues posed in the textbook. The NCERT 8 Science Solutions include easy-to-understand pictures and diagrams, so students will have no trouble understanding the answers. NCERT Solutions for Class 8th Science have been provided in a very easy manner by the creators. Complex scientific terminologies are taught in a clear and concise manner, using easy-to-remember and drawn illustrations.

NCERT science class 8 answers are available online. Students may access NCERT 8 science solutions by just tapping on them. Top NCERT Experts cross-check the NCERT Solutions for Class 8 in order to ensure that the NCERT (National Council of Education Research and Training) solutions are up to pace with the competition that students face. Apart from ensuring that students pass their Class 8 exams, NCERT Solutions for Class 8 Science also aims to improve student’s skill development in order to help them learn more effectively. The quality of NCERT Solutions for Class 8 is maintained by closely adhering to the standards and syllabus for Class 8 .

The most accurate NCERT Solutions for Class 8 Science are available here for download in FREE PDF format for you. Vedantu provides solutions of Class 8 Science in PDF format that you can download for FREE and can use from anywhere and anytime. Our best Science teachers have reviewed all the Class 8 NCERT Science questions before providing you with the solutions. Getting NCERT Solutions is no longer a tough task if you have reached Vedantu.

You can also Download NCERT Solutions for Class 8 Maths to get solutions to all exercises given in your NCERT textbook.

Detailed Overview of Class 8 Science NCERT Solutions

Overview of ncert solutions class 8 science.

Class 8 Science is one of the most important subjects in the curriculum of students. In this class, they are introduced to various concepts of Physics, Chemistry, and Biology. Students can learn a lot from the chapters of science in their syllabus. They will be introduced to important topics such as Microorganisms, Synthetic Fibres & Plastics, Coal & Petroleum, Cells, Conservation of Plants & Animals, Sound, Friction, Reproduction, Chemical Effects of Electric Current, etc. They can also master other topics such as Light, Force and Pressure, Pollution, etc. These topics not only build a strong conceptual foundation for students but also help them in their higher studies. Students can take help from the 8th Science Guide to further cement their knowledge about the topics.

The learned experts of Vedantu have formulated the NCERT Solution to help students learn chapters better. They can finish reading their textbook lessons and complete their syllabus with these solutions. Some of the chapters of Class 8 Science have significant weightage in the examinations. Thus, students can easily figure out the chapters that they need to focus more on. This will further help them in scoring better marks in their final exams. The experts have managed to create these solutions based on CBSE guidelines to provide further support for students. They will be able to figure out the examination pattern from these solutions. Also, they will be able to tackle difficult questions in their final exams to score more marks. Download 8th Science Book Back Answers right now for better guidance.

NCERT Solutions for Class 8 Science - Chapter-wise List

Given below are the chapter-wise NCERT Solutions for Class 8 Science. These solutions are provided by the Science experts at Vedantu in a detailed manner. Go through these chapter-wise solutions to be thoroughly familiar with the concepts.

NCERT Solutions for Class 8 Science | Chapterwise PDF

Hindi Medium | NCERT Solutions for Class 8 Science | Chapterwise PDF

Ncert class 8 science solutions - free pdf download.

What could be better than getting all the free CBSE Class 8 Science at one place? Gone are those days when you had to browse through different websites to get all the Class 8 Science NCERT Solutions at one place. Class 8 exam syllabus acts as a stepping stone for further higher classes where you might feel that the topics are out of your league and hard to comprehend. One very important thing to keep in mind is the concepts entailed in the Science syllabus form the backbone of higher classes. Having a weak base in Science can have its own consequences. Class 8 Science NCERT Solutions has covered all the chapters of Class 8 Science in detail which can be of great help to get your basic concepts cleared right away. You might want to go through details of all the chapters to know what are the important points in any particular chapter before you start to learn it. Knowing about the chapter beforehand can make you aware of how to proceed further and how to map your preparation by using NCERT Solution of class 8 Science. Below given are the chapter-wise details of science NCERT Class 8 Solutions .

NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management

Through this chapter, you will come to know how food is prepared by different agricultural practices. In this chapter, you will learn about Kharif crops and rabi crops. You will be able to understand basic practices of crop production which includes- 

Preparation of soil 

Sowing 

Adding manure and fertilisers 

Irrigation 

Protecting from weeds 

Harvesting 

You will also get to know about fertilisers and manure in this chapter. If you are also the one who generally gets confused between fertilisers and manure then you don’t need to worry now. As Vedantu has provided detailed difference between fertilisers and manure in Free PDF of NCERT Solutions Class 8 Science of Chapter 1 . You will study traditional and modern methods of irrigation and will be able to understand the agricultural journey of India. NCERT Solutions for Class 8 Science Chapter 1 includes solutions to all 11 questions given in your NCERT Textbook. It contains the solution of even word puzzles as well to help you to understand how to solve them. Apart from NCERT solutions, you can get a free article on winnowing and threshing agricultural practices on Vedantu. You will come to know about the many harvest festivals of India through this chapter. 

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 1 of CBSE Class 8 Science Solutions -

Chapter 1: Crop Production and Management Important Questions

Chapter 1: Crop Production and Management Revision Notes

Chapter 1: Crop Production and Management NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe 

Through this chapter, you will come to know about which microorganisms are useful and which are harmful. In this chapter, you will study major groups of microorganisms – bacteria, fungi, protozoa and algae. You will get to know about viruses, medicinal and commercial use of microorganisms. Where do Microorganisms Live? Microorganisms and Us, Harmful Microorganisms, Food Preservation, Nitrogen Fixation, soil Fertility and Nitrogen cycle are a portion of the primary topics covered in this chapter. NCERT Solutions for Class 8 Science of Chapter 2 includes solutions to all 9 questions given in your NCERT Textbook .

Important Topics Covered in Chapter 2: Microorganisms: Friends and Foes

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 2 of CBSE Class 8 Science Solutions -

Chapter 2: Microorganisms : Friend and Foe Important Questions

Chapter 2: Microorganisms : Friend and Foe Revision Notes

Chapter 2: Microorganisms : Friend and Foe NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics

You must have seen many kinds of clothes or fabrics. Have you ever thought of what these fabrics are made of? If yes, then this chapter is going to soothe your curiosity. In this chapter, you will study What are Synthetic Fibres? Kinds of Synthetic Fibres, Characteristics of Synthetic Fibres, Plastics, Impact of plastics on our environment and about three r’s methods. NCERT Solutions Class 8 Science of Chapter 3 includes solutions to all 15 questions given in your NCERT Textbook.

Important Topics Covered in Chapter 3: Plastic and Synthetic Fibres

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 3 of CBSE Class 8 Science Solutions -

Chapter 3: Synthetic Fibres and Plastics Important Questions

Chapter 3: Synthetic Fibres and Plastics Revision Notes

Chapter 3: Synthetic Fibres and Plastics NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 4 Materials: Metals and Non-Metals 

You will get introduced to the basics of Chemistry through this chapter. In this chapter, you will study metals, non-metals, their physical and chemical properties and their reactions with oxygen, water, acids, bases. You will study displacement reactions also. You will use the concept of indicators studied in Class VII in this chapter. You will get to know many different uses of metals and non-metals. After understanding this chapter, you will be able to classify matters into metals and non-metals based on their properties. Science NCERT Solutions Class 8 of Chapter 4 includes solutions to all 11 questions given in your NCERT Textbook. These questions will test your application, analysis skills and cognizance. 

Important Topics Covered in Chapter 4  Materials: Metals and Non-metals

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 4 of CBSE Class 8 Science Solutions -

Chapter 4: Materials : Metals and Non-metals Important Questions

Chapter 4: Materials : Metals and Non-metals Revision Notes

Chapter 4: Materials : Metals and Non-metals NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 5 Coal and Petroleum

In this chapter, you will study exhaustible and exhaustible natural resources. You will get to know how coal was formed? What are fossil fuels? Which products do we get by the process of processing coal? You will be able to know where we get petroleum, natural gas and which products do we get after refining petroleum.  The chapter additionally explains Natural Gas and how these important assets are getting depleted because of huge and uncontrolled usage. If you wonder how we get paraffin wax from petroleum, then this chapter is going to satisfy your curiosity. NCERT Solutions of Class 8 Science of Chapter 5 includes solutions of all 9 questions given in your NCERT Textbook. These questions will test your cognizance.

Important Topics Covered in Chapter 5 Coal and Petroleum 

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 5 of CBSE Class 8 Science Solutions -

Chapter 5: Coal and Petroleum Important Questions

Chapter 5: Coal and Petroleum Revision Notes

Chapter 5: Coal and Petroleum NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 6 Combustion and Flame 

You must have seen candle flame many times. Have you ever thought about why it looks mainly yellow in colour? If yes, then you will get an answer through this chapter. In this chapter, you will learn about flame, the structure of a flame, combustion, types of combustions, fuels, fuel efficiency, calorific value, global warming, acid rain, why different sorts of fuel are utilised for different purposes at home, in industry and for running autos and why some fuels give flame while others don’t. You will get to know how we control fire? NCERT Solutions of Class 8 Science of Chapter 6 includes solutions of all 13 questions given in your NCERT book. These questions will test your cognizance and mathematical skills. 

Important Topics Covered in Chapter 6 Combustion and Flame

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 6 of CBSE Class 8 Science Solutions -

Chapter 6: Combustion and Flame Important Questions

Chapter 6: Combustion and Flame Revision Notes

Chapter 6: Combustion and Flame NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 7 Conservation of Plants and Animals 

Conservation of Plants and Animals is a critical subject of Science. This part will push you to not just understand the human exercises that negatively affect nature's abundance but will introduce you to such practices by which we can protect and monitor the fauna and flora of our ecosystem. In this chapter, you will study deforestation, its causes and impacts, the importance of conservation of forest and wildlife, biosphere reserve, national parks, flora and fauna, endemic species, wildlife sanctuary, red data book, recycling of paper and reforestation. NCERT Solutions of Class 8 Science of Chapter 7 includes solutions to all 11 questions given in your NCERT book. These questions will test your cognizance, understanding and evaluating skills.

Important Topics Covered in Chapter 7: Plant and Animal Conservation

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 7 of CBSE Class 8 Science Solutions -

Chapter 7: Conservation of Plants and Animals Important Questions

Chapter 7: Conservation of Plants and Animals Revision Notes

Chapter 7: Conservation of Plants and Animals NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 8 Cell: Structure and Functions 

You must have thought about your body being made up of which substance? So, in this chapter, you will get to know about the smallest structural unit of organisms. In this chapter, you will study about the discovery of cells, the cell, different shapes and sizes of cells, cell structure and its functions, plant cell and animal cell, comparison of plant cell and animal cell. The chapter starts with the Discovery of Cell and explains some very interesting topics such as details of unicellular and multicellular organisms and different shapes of cells. NCERT Solutions of Class 8 Science of Chapter 8 includes solutions to all 10 questions given in your NCERT book. It includes the crossword question also for your better understanding. These questions will test your cognizance, understanding, evaluating skills and drawing skills. 

Important Topics Covered in Chapter 8: Structure and Functions of the Cell

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 8 of CBSE Class 8 Science Solutions -

Chapter 8: Cell Structure and Functions Important Questions

Chapter 8: Cell Structure and Functions Revision Notes

Chapter 8: Cell Structure and Functions NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 9 Reproduction in Animals 

You must have thought about how a new baby is born? In this chapter, you will get an answer to this question. In this chapter, you will study modes of reproduction, sexual reproduction, asexual reproduction, male and female reproductive organs, development of the embryo, sex determination, metamorphosis, cloning, budding etc. You have studied reproduction in plants in Class VII. In this class, this chapter covers reproduction in animals. NCERT Solutions of Class 8 Science of Chapter 9 includes solutions to all 10 questions given in your NCERT book. It includes the crossword question also for your better understanding. These questions will test your cognizance, understanding, evaluating skills and drawing skills.

Important Topics Covered in Chapter 9: Animal Reproduction 

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 9 of CBSE Class 8 Science Solutions -

Chapter 9: Reproduction in Animals Important Questions

Chapter 9: Reproduction in Animals Revision Notes

Chapter 9: Reproduction in Animals NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 10 Reaching the Age of Adolescence 

You, being a student of class 8 can easily relate to the content of this chapter. In this chapter, you will study adolescence, puberty, Adam’s apple, secondary sexual characters, the role of hormones in initiating reproductive function, reproductive health, menopause and menarche. NCERT Solutions of Class 8 Science of Chapter 10 includes solutions to all 9 questions given in your NCERT book. It includes the crossword question also for your better understanding. These questions will test your cognizance, understanding, evaluating and drawing skills.

Important Topics Covered in Chapter 10: Adolescent Development

Along with this, students can also download additional study materials provided by Vedantu, for Chapter 10 of CBSE Class 8 Science Solutions -

Chapter 10: Reaching The Age of Adolescence Important Questions

Chapter 10: Reaching The Age of Adolescence Revision Notes

Chapter 10: Reaching The Age of Adolescence NCERT Exemplar Solutions

NCERT Solutions for Class 8 Science Chapter 11 Force and Pressure 

This chapter will take you through the interesting world of physics by explaining to you the concepts of Force and Pressure. In this chapter, you will study force and its magnitude and direction, effects of force, different types of forces, the concept of pressure, the pressure exerted by liquids and gases and atmospheric pressure. NCERT Solutions of Class 8 Science of Chapter 11 includes solutions to all 10 questions given in your NCERT book. These questions will test your cognizance, understanding, evaluation and mathematical skills.

Important Topics Covered in Chapter 11: Fore and Pressure

Ncert solutions for class 8 science chapter 12 friction .

You must have noticed that the soles of shoes get worn out after using them for a long time. You will get the reason behind it after reading and understanding the concepts given in Chapter 12 of your NCERT book . In this chapter, you will get to know all about friction- its types, effects etc. The chapter starts with everyday life precedents and bit by bit presents the idea of Friction in its first area. Several diagrams and images help for better understanding and end up being a useful learning instrument. NCERT Solutions of Class 8 Science of Chapter 12 includes solutions to all 10 questions given in your NCERT book. These questions will test your cognizance, understanding, evaluation and mathematical skills.

Important Topics Covered in Chapter 12: Friction

Ncert solutions for class 8 science chapter 13 sound.

Chapter 13, Sound, talks about the distinction between music and noise. Noise pollution, its causes, impacts and control measures are explained towards the finish of the chapter. This chapter will take you through the concepts of Sound. This chapter will strengthen your base for future complex topics. NCERT Solutions of Class 8 Science of Chapter 13 includes solutions to all 10 questions given in your NCERT book. These questions will test your cognizance, understanding, evaluation and mathematical skills.

Important Topics Covered in Chapter 13: Sound

Ncert solutions for class 8 science chapter 14 chemical effects of electric current .

In Class VI, you would have made a tester to test whether a specific material enables the electric flow to go through it or not with the assistance of a teacher. Then you found out that metals, for example, copper and aluminium conduct electricity while materials, for example, rubber, plastic and wood don't conduct electricity. In this chapter you will study that many types of liquids or solutions conduct electricity or not, chemical effects of electric current, electroplating etc. NCERT Solutions of Class 8 Science of Chapter 14 includes solutions to all 12 questions given in your NCERT book. These questions will test your cognizance, understanding, and evaluating skills. 

Important Topics Covered in Chapter 14: Chemical Effects of Electric Current 

Ncert solutions for class 8 science chapter 15 some natural phenomena .

Some Natural Phenomena throw light on various phenomena of nature, for example, lightning and earthquakes. You will study the Causes, impacts, magnitude and properties of lightning in detail in this chapter. Furthermore, this chapter includes topics like lightning, Types of Charges and Their Interaction, Charging by Rubbing, Transfer of Charge, The Story of Lightning, Lightning Safety and Earthquakes. NCERT Solutions of Class 8 Science of Chapter 15 includes solutions to all 12 questions given in your NCERT book. These questions will test your cognizance, understanding, and evaluating skills.

Important Topics Covered in Chapter 15: Some Natural Occurrences

Ncert solutions for class 8 science chapter 16 light.

In this chapter, you will study laws of reflection, regular and diffused reflection, multiple images, kaleidoscope, the structure of the human eye, braille system, lateral inversion etc. NCERT Solutions of Class 8 Science of Chapter 16 includes solutions to all 17 questions given in your NCERT book. These questions will test your cognizance, understanding, evaluating and drawing skills. 

Important Topics Covered in Chapter 16: Light

Ncert solutions for class 8 science chapter 17 stars and the solar system .

You must have seen the moon and stars in the sky. Have you ever noticed any pattern of stars in the sky? In this chapter, you will study celestial objects, different patterns of stars, the Position of those objects, and their structure. The chapter starts by discussing the Moon, the Period of the moon, its situation in the close planetary system, the surface of the moon and the perception of the general population venturing on the moon surface is curiously depicted with the assistance of a basic language, outlines and exercises too. NCERT Solutions of Class 8 Science of Chapter 17 includes solutions to all 16 questions given in your NCERT book. These questions will test your cognizance, understanding, evaluating and drawing skills. 

Important Topics Covered in Chapter17: Solar System and Stars

Ncert solutions for class 8 science chapter 18 pollution of air and water.

In this chapter, you will study air pollution and water pollution. This chapter addresses the solution for these also. How does Air Get Polluted are some of the significant topics discussed in this chapter. NCERT Solutions of Class 8 Science of Chapter 18 includes solutions to all 11 questions given in your NCERT book. These questions will test your cognizance, understanding and evaluating skills. 

Important Topics Covered in Chapter 18: Pollution of Air and Water

Why is vedantu the best class 8 science solution provider.

Whether you're doing homework or preparing for an exam, you may utilise our NCERT Solutions for CBSE Class 8 Science at any time. All of our CBSE Class 8 solutions are written using the most up-to-date CBSE Class 8 syllabus and are regularly updated. Our free CBSE Class 8 Science Textbook Solutions can help you enhance your test scores by strengthening your fundamentals.

Our study resources, such as CBSE Class 8 Sample Paper 2024-25, are created by subject matter experts with several years of experience in teaching CBSE students. For students' convenience, we give textbook answers such as NCERT Solutions CBSE Class 8 Science, which contain simplified solutions to textbook questions for each chapter. Students may use our CBSE Class 8 Science Solutions to complete assignments and understand all of the ideas and topics included in the NCERT Class 8 Science syllabus.

Why Are NCERT Science Solutions for Class 8 So Important?

Class 8 NCERT Solutions Science broadens the foundation for conceptual understanding. Because the textbook lacks a full description of the syllabus or answers, it gives a comprehensive perspective of the required curriculum. All of Class 8 Science major theories and formulae have been thoroughly solved, which aids in the formation of concepts and the discovery of new connections between them. 

Importantly, Vedantu's NCERT Science Solution for Class 8 is a valuable resource for students preparing for competitive exams such as NRRT, IIT JEE, BITSAT , and VITEEE , among others. The knowledge of topics becomes straightforward and in-depth when the NCERT book is complemented by these answers. Furthermore, because it is structured to provide a step-by-step explanation, students can go right to the solutions. Ace your Science preparation by using Vedantu's Class 8 NCERT Science resources.

What Are the Benefits of Referring Class 8 Science NCERT Solutions?

If we start mugging up the facts, we find that Science has its evidence in a plethora of unforgettable inventions and discoveries that have proved highly beneficial for mankind including daily life implementations. In other words, Science is regarded as the most important subject when it comes to school-level and other exams and the best way to understand the concepts is by referring to Science NCERT Solutions Class 8 . Understanding the fundamentals of Science taught in Class 8 is critical and the Science NCERT book is your gateway to good marks in the exam. Also, solving previous year questions papers and sample papers becomes very easy for you.

You can download the FREE PDF of NCERT solutions of Science Class 8 and use it at your convenient time and place without having an internet connection. A with the help of NCERT Science Solutions for Class 8 covering each and every chapter on this page. The NCERT Solutions for Class 8 Science will help you solve all the Class 8 Science questions smoothly. You can also share the link to our free CBSE Class 8th Science NCERT solutions with your classmates to let them utilise the solutions.

Once you have mastered the way to comprehend 8th class science, then you should not leave any stone unturned. This means that on a priority, you need to grasp all the important fundamentals that are considered under the school syllabus, i.e. under the textbooks provided by NCERT and then move to any other reference book. This will change your problem-solving strategy exponentially, especially with all the NCERT Solution of class 8 Science in one place, you can easily get a detailed insight into the subject.

Vedantu Gives You the Competitive Edge

Students who are in search of additional guidance while going through our Class 8 Science NCERT solutions can anytime sign-up for Vedantu LIVE Online Classes. The sessions are conducted by some of the best science teachers across the country. You can also talk to the teacher just like you would in a normal tuition class.

Our Online Tutoring Team is always ready to help you if you are stuck with any questions. You can get tutoring in NCERT Solutions Class 8 Science from the comfort of your home without bothering about getting stuck in traffic, being late, or your safety! Our Science tutors are highly distinguished and focus on clearing your concepts and providing you with a detailed understanding of the topics along with NCERT Solution for Class 8 Science. As the classes are LIVE, you can easily interact with the teacher at any point in time.

To monitor your progress, you are regularly tested by our Science tutors. One of the most important benefits of learning with Vedantu is that you get to choose the pace of the learning and the timing of the live tutoring session. All the lesson plans are structured according to your requirements. The live sessions are recorded and available absolutely free of cost to students and their parents for review and revision purposes later. Much to your delight, you can also study CBSE NCERT Science class 8 solutions on your PC or even through your Android mobile devices after downloading Vedantu instant doubt solving app! Enrol with us as a regular student or whenever you have doubts and want to prepare for your tests or examinations! All we want is our NCERT Solutions for Class 8 Science to prove helpful for you and enable you to perform great at exams!

You are often unable to utilise a hundred percent of your time if you get stuck with some particular question. What follows next is you are forced to analyse the solution repeatedly and from different angles, which usually leads to poor time management. Through Vedantu’s online platform, you gain access to quality content by an expert teacher who can instantly provide solutions to even complex questions. This enables you to cover more topics at the same time, leading to better preparation for any examination.

NCERT (National Council of Education and Research) is an autonomous organisation that sets the curriculum for schools across India including all the CBSE schools. Set up in 1961 by the Government of India, the main agenda of the council is to promote quality learning and coordinate research in the areas related to school education. NCERT published prescribed textbooks that are mandatory for schools to follow. 

Science is the most important subject in school education as it incorporates all the crucial information related to human existence and its surroundings. Class 8 NCERT Science introduces students to the world of science in a significant way. Some of the most important chapters are taught in 8th standard Science including Crop Production and Management, Coal and Petroleum, Reproduction in Animals, Force and Pressure, Friction, Sound, Light etc. 

NCERT Solutions for Class 8 Science are provided to students to help them understand how to write answers in exams correctly. NCERT Solutions help them find answers to the textbook questions that they struggle to find at one place. These solutions are provided by expert teachers who have years of experience in the field of teaching. So, students can be assured of the quality of solutions. 

Science is one of the mainstream subjects from a career point of view. Achieving good grades in the Class 8 CBSE Science examination not only improves a student’s academic records but boosts his/her confidence to pursue a career in the field of Science. For those who are interested in the subject, the knowledge of the subject opens up doors for many career opportunities in the field of Medical Science, Engineering, Research etc. Class 8 CBSE Science subject involves fascinating concepts related to humans, animals, plants, light, electric current, force and pressure, etc. 

Class 8 Science: Chapter-wise NCERT Solutions

The importance of NCERT Science concepts cannot be denied in our in-depth understanding of nature and human anatomy. Class 8 Science includes chapters related to all the three major domains under Science: Physics, Chemistry and Biology. The topics explained in the Class 8 Science CBSE syllabus involve a lot of concepts related to daily life. Students must try to understand each chapter properly and this is where NCERT Solutions come into play. However, you must source NCERT Solutions for Class 8 Science from trustworthy websites that include chapter-wise solutions and are available for free download. As per the latest CBSE syllabus, the NCERT textbook for Class 8 Science includes 18 chapters:

Crop Production and Management

Microorganisms: Friend and Foe 

Synthetic Fibres and Plastics

Materials: Metals and Non-Metals

Coal and Petroleum

Combustion and Flame

Conservation of Plants and Animals

Cell- Structure and Functions

Reproduction in Animals

Reaching the Age of Adolescence

Force and Pressure

Chemical Effects of Electric Current

Some Natural Phenomena

Stars and the Solar System

Pollution of Air and Water

Students will be benefited from the chapter-wise NCERT Solutions for Class 8 Science textbook problems during their exam preparation. The latest NCERT syllabus of Class 8 Science designed for CBSE students involves chapters that contribute heavily towards building the subject foundation needed for higher studies. Students interested in professions closely related to the fields of Science must pay attention to Class 8 Science chapters. The Class 8 exam is an important milestone that prepares students for the Class 10 board exam. Science is one of the most interesting subjects for many students. If students prepare well for the subject, scoring in a Science paper is not such a difficult task. 

Class 8 Science CBSE syllabus prescribed as per the guidelines by NCERT (National Council of Educational Research and Training) includes important concepts. In chapters like Cell- Structure and Functions, Reproduction in Animals and Reaching the Age of Adolescence, basics about the human body and mammals, in general, are taught. Students can learn about chemical properties of a matter in chapters like Synthetic Fibres and Plastics, Materials: Metals and Non-Metals, Coal and Petroleum, Combustion and Flame, etc. topics that involve the study of Physics are Force and Pressure, Friction, Sound etc. Hence, students are provided with basic knowledge on important Science topics in the Class 8 Science NCERT textbook. Download the free PDF version of NCERT Solution for Class 8 Science and clear all your doubts right away!

Tips To Score Well in Class 8 Science Exam Paper

Science is one of the most important subjects during school studies. Moreover, the subject finds its application in various fields of studies and is one of the most opted streams of higher education. Hence, it is imperative for students to pay attention to Science concepts from a young age. Following are some of the tips to perform well in the Class 8 Science CBSE exam:

Follow a Systematic Study Plan : In order to score well in any paper, it is important to have a study routine devised in a way that allows time for revision and focusing on chapters you are weak at.

Refer NCERT Solution: For those who are finding it difficult to solve the NCERT textbook problems themselves can refer to NCERT Solutions and get all their doubts cleared. NCERT Solution helps them to write the answer without clearly explaining the concepts without making any mistakes.

Revise Thoroughly: Students should never underestimate the importance of having a thorough revision of the chapters to achieve good grades in exams

Take Proper Rest and Indulge in Recreational Activities: Along with studies, it is important to have time for proper rest and leisure activities. Do not overburden yourself with studies as it would unnecessarily increase your exam stress.

Make aLlist of the Most Important Topics in the Syllabus: The first and most simple tip that will benefit you the most is to make a list of all the important concepts and formulas for rapid reference and review. By listing the chapters, you will not miss any key topics and will be able to simply revise each subtopic and subject. You may also recollect concepts just by looking at the list and will be able to retain everything learnt on the day of the Science exam. 

Clear all Doubts as Soon as Possible: Another crucial tip while preparing for the Class 8 Science exam is to seek clarification on doubtful topics from your teacher as soon as feasible. Hesitating to express your uncertainty will just add to your perplexity and lead to a loss of confidence.

NCERT Textbooks Must be Studied Extensively: Concentrate on the NCERT curriculum, as it has the most up-to-date solved examples. Prepare all of the NCERT questions and examples to ace the CBSE Class 8 Science examination. 

Previous Year Question Papers: Solve as many previous year question papers as you can as this will help you figure out which questions have been asked how many times, as well as the marks assigned to each question. It also provides you with an indication of how long your answer should be from an examination viewpoint. Solving papers also helps you understand the various ways the same question has been asked in the exam and how to respond to it.

Try to Write More: Thoroughly read the syllabus topics, but be sure you can write what you read. Writing, rather than just reading, has been shown to aid in the retention of any concept for a longer period of time. Writing provides practice and helps to write better and well-structured answers in the exam. It also helps you understand your writing pace and modify it accordingly during the examination.

Time Management: Effective time management will assist students in completing their exam papers on time, eliminating last-minute worry and tension. Students can do this by creating a timetable that helps in allocating adequate time to each topic. 

Start Preparing as Soon as Feasible: The earlier you start preparing for the Science exam, the sooner you will be able to complete the syllabus. This will allow you to revise the syllabus multiple times and leave enough time for you to improve on tougher topics from the syllabus. Aim to complete the syllabus at least 3 months before the day of the final exam to get adequate revision and practice time. 

Always Make an Effort to Establish a Learning Environment Around You: The atmosphere you build before your final examinations will play an essential role in Science exam preparation. As a class 8 student, you must strive to provide yourself with a comfortable, peaceful, and distraction-free atmosphere.

Study in Chunks: Divide the entire syllabus into difficult, moderately difficult and easy portions. Simplify your preparation as much as possible by further dividing a chapter into subtopics sub-sub-topics. Attempt to incorporate small pauses when studying for a long period of time. Never let anything stand in the way of you enjoying your favourite activities and hobbies.

Try to Study When Your Attention is at its Peak: If you are a morning person, prepare your tough portion of the syllabus before noon, and if you are a night person, plan your study hours accordingly. Based on your unique strengths and weaknesses, study at a time when you are the most productive and least susceptible to distractions. 

Attempt to Make the Most of Every Opportunity: When studying for your examinations, try to arrange small breaks into your timetable. Use the free time to catch up on missed reading or to concentrate on Science problems. Always remember to make the most of each and every opportunity to ace the Science exam. 

Study Systematically: Many students have the habit of going right into answering the exercises without first reading the theoretical section of the chapter from the NCERT. You won't have a clear comprehension of the subject until you read the theory. If you want to solve all the questions correctly, make the habit of studying the topics first and then move on to the back exercises. 

Use Mnemonics, Flowcharts and Flashcards: It is scientifically proven that the use of handmade mnemonics, flashcards and flowcharts will help you to memorise and retain even the toughest topics of the Science syllabus for long. It will also help you revise the syllabus quickly and easily. 

Don't Ignore the Diagrams: Diagrams given in the Science syllabus must be practised well before appearing in the Science exam. Several questions require you to draw diagrams, thus, don't ignore the diagrams and practice them regularly. Use a pencil to draw the diagrams and label them appropriately in legible handwriting. 

Study Wisely: If you've already mastered a topic, just writing key definitions 10 to 15 times is a waste of time. Instead, you might utilise that time to study new topics. Study wisely and know what kind of questions are most likely to be asked in the Science exam by analysing the previous year papers. First, complete the most important topics from an examination point of view and then move on to the least important topics. 

Why Vedantu?

Vedantu is a great platform for accessing all the study-related solutions. The NCERT Solution for Class 8 Science is a well-created tool for CBSE students studying in Class 8. Vedantu is known to cater to exceptional study materials that help students to prepare for the exam. The most accurate solutions are provided to students as they are framed by the subject matter experts who have years of teaching experience. 

Vedantu offers NCERT Class 8 CBSE Solutions in a free to download PDF format that includes chapter-wise solutions to the exercise problems. Since it is available online, students can access it whenever they want to. We provide NCERT Solutions for all the subjects including Maths, English, Social Science, etc. We also provide sample test papers, revision notes, important questions, syllabus, etc. as a part of our study material.  

You must choose Vedantu as it has a track record of successfully mentoring young kids in their academic development. Vedantu has a panel of highly qualified and experienced mentors working relentlessly to offer easy and fun ways of learning. Vedantu believes that learning has to be fun and exams should be less stressful for students. With the same goal, Vedantu caters to online mentoring where students are taught with practical examples, graphs and are given fun-to-do exercises that keep them engaged. Students can register for Vedantu’s LIVE Interactive session and see the difference themselves. All the study materials that we offer at Vedantu are regularly reviewed by the expert team. Hence, students can be assured of the quality of these materials. You can avail all the study materials absolutely free of cost. So, what are you waiting for? Achieve the academic excellence that you aim for with Vedantu. Download Vedantu App and be a part of the fun yet fruitful learning. 

Vedantu’s online learning solutions ensure that you can avail the best study materials at the comfort of your homes without travelling far for tuition. Get all the necessary assistance anytime, anywhere! You can get all your doubts cleared with the help of the excellent mentoring team at Vedantu. Just register for online tuition. 

NCERT Solution for Class 8 Science is a great way to clear all your subject related doubts and score well in the Class 8 CBSE exam. There are many online platforms that offer Class 8 CBSE NCERT Solution in free to download PDF format. Students should carefully choose which platform they want to use to procure all the necessary study material. One such platform is Vedantu that provides 100% accurate NCERT Solution and other study material free of cost for students to prepare for their exams. Get your copies now!

NCERT Solutions for Class 8th Science Have Many Advantages

The following are some of the advantages of solving the NCERT Solution for Class 8 Science:

Provides in-depth Knowledge in Simple Language: All NCERT Solutions at Vedantu have been solved by top academic professionals, and the Class 8 Science NCERT Solutions have been written in a way that any student can comprehend. 

Follows the Latest and updated CBSE Curriculum: All NCERT book questions for Science Class 8 have been answered step-by-step keeping in mind the CBSE marking scheme. 

Provides Crystal Clear Understanding of Basics: All of the fundamentals have been covered, and the solutions have been described using principles, rules, and concepts from the chapter. Our experts have provided the solutions in an easy language with adequate reasoning. 

Helpful for Competitive Exams: Solving the challenging and higher-order thinking skills based problems necessitates in-depth knowledge as well as a method for arriving at the correct answer fast. If you study from these NCERT Science Solutions, you will be able to easily handle questions in competitive exams such as JEE, NEET, and Olympiads.

It Will Help You in Completing Your Assignments on Time: It Will Assist you in completing your assignments on time and you no more need to depend on expensive coaching and tuition classes. However, we urge that you attempt to answer the questions on your own first. If you're having trouble understanding, look over Vedantu's NCERT Class 8th Science Solutions.

Helps You Revise a Large Syllabus in Less Time: With its crisp, lucid, and well-structured solutions and notes, Vedantu's NCERT Solutions aids you in last-minute revisions a few days before the examination. All key terminologies, definitions, and concepts are consolidated here for your convenience. You will save a lot of time and have a stress-free last revision before the Science exam if you revise Vedantu's study materials.

Updated on a regular basis and based on the most recent exam pattern, syllabus, and marking scheme: Because it is based on the most recent and up-to-date exam criteria, Vedantu's NCERT Science Solution is the most reputable and trustworthy source for preparation. Changes in the CBSE Syllabus, exam format, or marking scheme are taken into account, and Vedantu's study materials are updated appropriately. This provides Vedantu with a competitive advantage over other online sites offering NCERT Class 8 Science Solutions.

Error-Free, High-Quality Solutions: Vedantu's solutions include no flaws or inaccuracies. Our primary focus has always been to give answers that can assist students to get an understanding of topics and questions that they find tough or difficult to handle. To that end, we constantly prioritise excellent solutions that are error-free.

Solutions that are Simplified and Easy to Remember: We understand that one of the biggest challenges that students encounter is that they are often unable to grasp topics that are delivered in a difficult or complex manner. We address this issue by offering Vedantu's NCERT Solutions, which are presented in an easy-to-understand and uncomplicated style. The solutions contain all topics and details while also guaranteeing that class 8 students can understand them.

Solutions Help Clarify Your Doubts : The syllabus of Class 8 Science is very vast and contains advanced topics that might be difficult for some students to comprehend. Thus, there might be some topics where you can have some doubts. With the help of NCERT solutions, you can clarify any doubts that you have about any particular chapter or topic. Also, these solutions help students compare their own answers to find out areas where they need improvement. Thus they can easily rectify their mistakes with these solutions.

Help in Improving Skills of Answering : The subject matter experts of Vedantu have formulated these answers according to the latest guidelines set by CBSE. Thus, students can easily figure out the answering format and can tackle difficult questions as well. This will help in improving the answering skills of students and improve their ability to score more marks. With the assistance of NCERT solutions, students can definitely achieve positive results in their exams.

Other Salient Features of Vedantu's NCERT Science Solutions Class 8

It enables you to quickly grasp all concepts and solve tasks without difficulty.

As a fast revision material, it assists you in your Class 8 Science examination preparation.

All solutions are written in plain English to ensure a complete understanding of the subject.

It provides you with in-depth subject knowledge and increases your exam confidence.

With the aid of NCERT Solutions PDF's Step by Step Solutions, you can grasp the ideas quickly.

NCERT Solutions PDF is available for free download and can be accessed both online and offline.

We hope that the information provided above about NCERT Solutions for Class 8 Science helps you a lot throughout your preparation. The NCERT Textbook Solutions PDF also assists students in quickly resolving all of their questions. Additionally, stay up to date with our site for updated NCERT Solutions for all grades and subjects.

With Vedantu, you can study all of your elementary, middle, and high school courses in a fun and interesting way. So, become a part of the world's largest and most comprehensive source of CBSE textbook solutions by downloading your copy of NCERT Solutions for Class 8 Science PDF RIGHT NOW! Stay connected with us to receive the most recent information on NCERT Books, NCERT Solutions for all courses, MCQs with Answers, and more.

If you're having trouble understanding the answer to a question, please let us know at our email [email protected]. Everything is provided in the form of individual PDF files. Vedantu has provided Class 8 Science notes, sample papers, chapter tests, and other study materials free of cost. If at all possible, please provide feedback and recommendations to help enhance the material and quality. We're constantly upgrading the material based on student feedback.

We are confident that the material offered in Vedantu's NCERT Solutions PDF for Class 8 Science will be of great use to you. You don't need to look elsewhere for additional study materials as we provide everything from MCQ Questions for 8th Science with Answers, NCERT Books for Class 8 , Chapter-by-Chapter Notes, to preparation suggestions and tips. All of these resources and study materials are available for free at Vedantu. Vedantu also provides free access to high-quality books and standard sources for Science exam preparation. So, for better preparation, go to the website and receive access to all of the most updated study tools as well as NCERT Solutions for every chapter.

Make Exam Prep Easy With NCERT Science Book Class 8 Solutions PDF Free Download

Download free PDF files of NCERT Solutions Class 8 Chapter Wise Solutions and have the right support to ace your exams. Students will find these study resources extremely helpful as they can easily complete the vast science syllabus without any trouble. They will be able to clarify doubts, formulate a proper preparation strategy for exams, and solve questions easily with these solutions from Vedantu. Download the study resources right now and prepare well for the exams.

Important Related Links for NCERT Class 8

CBSE Class 8 Revision Notes

NCERT Books for Class 8

Important Questions for CBSE Class 8

NCERT Exemplar Solutions for Class 8

CBSE Class 8 Syllabus

FAQs on NCERT Solutions For class 8 Science

1. Which are the Main Chapters of the NCERT Class 8 Science Textbook to Score Well in Exams?

NCERT Class 8 Science textbook consists of 18 chapters in total. The chapters are Crop Production and Management, Microorganisms: Friend and Foe, Synthetic Fibres and Plastics, Materials: Metals and Non-Metals, Coal and Petroleum, Combustion and Flame, Conservation of Plants and Animals, Cell- Structure and Functions, Reproduction in Animals, Reaching the Age of Adolescence, Force and Pressure, Friction, Sound, Chemical Effects of Electric Current, Some Natural Phenomena, Light, Stars and the Solar System and Pollution of Air and Water. All the chapters are equally important from the examination point of view. Most of these chapters are important to set the foundation for Class 10 Science. It is important to not skip any chapter if a student wants to score high in the exams.

2. Why Should I Refer to NCERT Solutions for Class 8 Science while Exam Preparation?

NCERT Solutions for Class 8 Science provides chapter-wise solutions to textbook problems. This will be extremely helpful for students during their exam preparation. CBSE students can refer to the latest NCERT Solutions for Class 8 Science designed by experts at Vedantu. This involves chapters that contribute significantly to building the subject foundation right from the beginning. Students who want to pursue Science or related subjects during their higher studies must pay attention to Class 8 Science chapters. The Class 8 Science exam is an important milestone that evaluates students’ aptitude for the subject. Hence, students must prepare well for the exam. If students refer to NCERT Solutions for Class 8 Science prepared by expert teachers at Vedantu, scoring well in the Science paper will be a cakewalk.

3. Is NCERT Book Enough for CBSE Class 8 Science Students to Gain Subject Knowledge?

NCERT Science textbook for Class 8 is designed exceptionally well for Class 8 students. It includes many interesting as well as important chapters to expand the horizons of knowledge. The Class 8 Science book prescribed for students by NCERT is written in a fairly simple manner with a lot of colourful diagrams and pictures to intrigue students. It is advised to students that they strictly follow the NCERT textbook and practice the questions given in the exercises and examples. Students are not required to do anything extra to score well in exams.

4. What are the concepts explained in the solutions of NCERT Class 8 Science Textbook?

Studying science is fun when concepts are made clear to students. This is because Science is all about putting practical knowledge to the test after studying the theory portion of a subject. In Physics, importance is given to understanding elementary mechanics conceptually. In contrast to this, cellular structures are explained in detail in Biology whereas periodic properties concepts are dealt with in Chemistry. You can access these solutions at Vedantu NCERT Class 8 Science Solutions .

5. What are the advantages of using the NCERT Solutions for Class 8 Science?

Practicing questions frequently is the trick to scoring well in examinations. At the end of each chapter in the NCERT Class 8 Science textbook , many exercises are provided for the benefit of students. These enable students to evaluate themselves. Vedantu NCERT Class 8 Science Solutions provides the answers to all the questions given in these exercises. In case you are stuck at any question and need assistance, this one will help you out. 

6. How many chapters are there in Class 8 Science?

There are 18 chapters in total in the NCERT Class 8 Science textbook. These chapters cover topics from all the three main branches of Science, namely Physics, Chemistry, and Biology. Each chapter is written in simple language to enable students to grasp concepts better and understand the course material easily. In case you want an overview of the chapter list and topics discussed in each chapter visit the page NCERT Solutions for Class 8 Science.

7. What is science for 8th class?

Science in class 8 is not divided into Physics, Chemistry, and Biology. CBSE students have a single NCERT textbook that deals with topics from each of these subjects. There are 18 chapters in total. The first chapter is Crop Production and Management while the last chapter is Pollution of Air and Water. Generally, chapters like Cell and Light hold more weightage. Also, many questions in the examinations are asked from here.

8. From which chapter in Class 8 Science are the most questions asked?

There are always a few high-yielding topics that more questions are set from in any examination. When it comes to class 8 Science, chapters like Cell and Light cannot be skipped if one wants to score good marks. Conservation of Plants and Animals and Pollution of Air and Water are chapters dealing with the environmental side of things. This is why referring to Vedantu CBSE NCERT Class 8 Science Solutions is of utmost importance where resources are available at free of cost. Students can also access all the study material on the Vedantu app.

NCERT SOLUTIONS FOR CLASS 8

Cbse class 8 study materials.

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Assignments Class 8 Science PDF Download

Students can refer to Assignments for Class 8 Science available for download in Pdf. We have given below links to subject-wise free printable Assignments for Science Class 8 which you can download easily. All assignments have a collection of questions and answers designed for all topics given in your latest NCERT Books for Class 8 Science for the current academic session. All Assignments for Science Grade 8 have been designed by expert faculty members and have been designed based on the type of questions asked in standard 8 class tests and exams. All Free printable Assignments for NCERT CBSE Class 8, practice worksheets, and question banks have been designed to help you understand all concepts properly. Practicing questions given in CBSE NCERT printable assignments for Class 8 with solutions and answers will help you to further improve your understanding. Our faculty have used the latest syllabus for Class 8. You can click on the links below to download all Pdf assignments for class 8 for free. You can get the best collection of Kendriya Vidyalaya Class 8 Science assignments and questions workbooks below.

Class 8 Science Assignments Pdf Download

CBSE NCERT KVS Assignments for Science Class 8 have been provided below covering all chapters given in your CBSE NCERT books. We have provided below a good collection of assignments in Pdf for Science standard 8th covering Class 8 questions and answers for Science. These practice test papers and workbooks with question banks for Class 8 Science Pdf Download and free CBSE Assignments for Class 8 are really beneficial for you and will support in preparing for class tests and exams. Standard 8th students can download in Pdf by clicking on the links below.

Subjectwise Assignments for Class 8 Science

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MCQ Questions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe with Answers

We have compiled the NCERT MCQ Questions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe with Answers Pdf free download covering the entire syllabus. Practice MCQ Questions for Class 8 Science with Answers on a daily basis and score well in exams. Refer to the Microorganisms: Friend and Foe Class 8 MCQs Questions with Answers here along with a detailed explanation.

Microorganisms: Friend and Foe Class 8 MCQs Questions with Answers

Choose the correct option.

Question 1. Tiny organisms which cannot be seen with the naked eyes are called (a) microorganisms (b) animals (c) fungi (d) bacteria

Answer: (a) microorganisms

Question 2. Microorganisms are also known as (a) yeast (b) microbes (c) viruses (d) Amoeba

Answer: (b) microbes

Question 3. Fungus can be seen with a (a) microscope (b) telescope (c) magnifying glass (d) both (a) and (c)

Answer: (d) both (a) and (c)

Question 4. Microorganisms that causes disease are also known as (a) pathogens (b) fungi (c) antigen (d) microbes

Answer: (a) pathogens

Question 5. Pathogens are also called (a) germs (b) antigen (c) antibody (d) carrier

Answer: (a) germs

Question 6. Bacteria are ______ organisms. (a) multicellular (b) unicellular (c) bicellular (d) tricellular

Answer: (b) unicellular

Question 7. Bacilli are the bacteria that are (a) rod-shaped (b) comma-shaped (c) curved-shaped (d) spiral

Answer: (a) rod-shaped

Question 8. Spherical-shaped bacteria are called (a) bacilli (b) vibrio (c) spirilla (d) cocci

Answer: (d) cocci

Question 9. Simple, plant-like microorganisms are called (a) algae (b) bacteria (c) both (a) and (b) (d) protozoa

Answer: (a) algae

Question 10. Medium that transmits pathogens from an infected person to a healthy one is called (a) fungi (b) germs (c) carrier (d) none of these

Answer: (c) carrier

Question 11. Medicine that kills or stops the growth of harmful disease-causing microbes is known as (a) antibiotic (b) antibody (c) antigen (d) vaccine

Answer: (a) antibiotic

Question 12. The process in which sugar in the food is transformed into alcohol and carbon dioxide by using microorganisms is known as (a) transformation (b) beverage (c) fermentation (d) respiration

Answer: (c) fermentation

Question 13. The fungus that is commonly used in bakery and beverage industries is (a) Penicillium (b) Yeast (c) Agaricus (d) Rhizopus

Answer: (b) Yeast

Question 14. Giardia is listed under the category of (a) fungi (b) protozoa (c) bacteria (d) algae

Answer: (b) protozoa

Question 15. Substance used to produce immunity against diseases in the living body is called (a) immune (b) vaccine (c) antibody (d) antigen

Answer: (b) vaccine

Question 16. How much nitrogen is present in the atmosphere? (a) 78% (b) 88% (c) 68% (d) 58%

Answer: (a) 78%

Question 17. Malaria is caused by which type of microbe? (a) Bacteria (b) Fungi (c) Algae (d) Protozoa

Answer: (d) Protozoa

Question 18. Common cold is caused by which type of microbe? (a) Bacteria (b) Virus (c) Algae (d) Fungi

Answer: (b) Virus

Question 19. Which of the following diseases is caused by a fungus? (a) Cholera (b) Common cold (c) Ringworm (d) Dengue

Answer: (c) Ringworm

Question 20. Antibiotics are effective against (a) bacteria (b) algae (c) viruses (d) all of the above

Answer: (a) bacteria

Question 21. Penicillin was discovered by (a) Edward Jenner (b) Louis Pasteur (c) Alexander Fleming (d) Robert Koch

Answer: (c) Alexander Fleming

Question 22. Mushroom belongs to the group of (a) algae (b) viruses (c) fungi (d) none of these

Answer: (c) fungi

Question 23. Amoeba belongs to (a) algae (b) fungi (c) protozoa (d) viruses

Answer: (c) protozoa

Question 24. Scientist who discovered fermentation is (a) Alexander Fleming (b) Louis Pasteur (c) John Mendel (d) Edward Jenner

Answer: (b) Louis Pasteur

Question 25. Microorganisms are (a) unicellular (b) multicellular (c) both (a) and (b) (d) none of these

Answer: (c) both (a) and (b)

Question 26. The microorganisms that cause diseases in human beings, plants and animals are called (a) carriers (b) mosquitoes (c) pathogens (d) antibodies

Answer: (c) pathogens

Question 27. Who discovered the vaccine for smallpox? (a) Louis Pasteur (b) Alexander Fleming (c) Joseph Lister (d) Edward Jenner

Answer: (d) Edward Jenner

Question 28. The algae commonly used as a fertiliser are (a) staphylococcus (b) diatoms (c) blue-green algae (d) none of these

Answer: (c) blue-green algae

Question 29. The microorganisms smaller than bacteria are (a) viruses (b) protozoan (c) fungi (d) algae

Answer: (a) viruses

Fill in the blanks with suitable word/s.

Question 1. Bacteria, fungi, protozoa and _______ are the major four groups in which microorganisms are classified.

Answer: algae

Question 2. Two microorganisms which live in symbiotic association in lichens are _______ and _______

Answer: algae, fungus

Question 3. We use a _______ to see the microorganisms.

Answer: microscope

Question 4. _______ are considered different from other microorganisms because they can multiply only by entering, the host organisms.

Answer: Viruses

Question 5. The gas released during the preparation of bread is _______

Answer: carbon dioxide

Question 6. The disease caused by a protozoan and spread by an insect is _______

Answer: malaria

Question 7. _______ are curved-shaped bacteria.

Answer: Vibrio

Question 8. Saprophytes and _______ are the two main categories of fungi.

Answer: parasites

Question 9. _______ are the threads of the multicellular fungi.

Answer: Hyphae

Question 10. Yeast is a _______ fungus.

Answer: unicellular

Question 11. Protozoa are _______ in nature.

Answer: heterotrophic

Question 12. Flu, cough and cold are caused by _______

Answer: viruses

Question 13. The first antibiotic discovered was _______

Answer: penicillin

Question 14. _______ are the microorganisms that help in the process of decomposition.

Answer: Decomposers

Question 15. The process of formation of curd from milk is known as the _______ of milk.

Answer: curdling

Question 16. All microorganisms are ………………….. harmful.

Answer: not

Question 17. Rhizobium is found in the root nodules of ………………….. plants.

Answer: leguminous

Question 18. Alcohol is produced with the help of …………………..

Answer: yeast

Question 19. ………………….. is a single-celled microorganism.

Answer: Amoeba

Question 20. The food material which is preserved by pasteurisation is …………………..

Answer: milk

Question 21. Disease-causing microorganisms are called …………………..

Answer: pathogens

Question 22. An edible fungus is …………………..

Answer: mushroom

Question 23. The antibiotic, first discovered by Alexander Fleming is called …………………..

Question 24. As a result of nitrogen cycle, the percentage of nitrogen in the atmosphere remains more or less …………………..

Answer: constant

Question 25. ………………….. is used in the preparation of bakery products.

Answer: Yeast

True or False

Question 1. Microbiology is the science of study of microbes.

Answer: True

Question 2. All the microorganisms are harmful.

Answer: False

Question 3. An instrument called microscope is required to see the microorganisms.

Question 4. Bacteria have an organised nucleus.

Question 5. Microorganisms are found in large number around us.

Question 6. Viruses are the most useful microbes.

Question 7. Anabaena is listed in the category of algae.

Question 8. Algae tend to develop on wet surfaces.

Question 9. Amoebic dysentery is caused by algae.

Question 10. A fungi is used in the production of alcohol.

Question 11. Jellies, jams and squashes are preserved by adding vinegar to them.

Question 12. Salt is used as a food preservative.

Question 13. Oxygen alone constitutes 78% of air.

Question 14. Mushroom is a fungus.

Question 15. Oxygen and nitrogen make up 78% of the air.

Question 16. All microbes are disease-causing.

Question 17. Virus can only multiply in living cells.

Question 18. Foot and mouth disease is a bacterial disease in animals.

Question 19. Bacteria can be killed by the use of antibiotics.

Question 20. Edward Jenner discovered the process of fermentation.

Question 21. Microorganisms can be seen with naked eyes.

Question 22. The bread dough rises because of the growth of yeast cells.

Question 23. Algae contain chlorophyll and thus are autotrophs.

Match the Following

Hope the information shed above regarding NCERT MCQ Questions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe with Answers Pdf free download has been useful to an extent. If you have any other queries of CBSE Class 8 Science Microorganisms: Friend and Foe MCQs Multiple Choice Questions with Answers, feel free to reach us so that we can revert back to us at the earliest possible.

• NCERT Exemplar
• NCERT 8 Science Exemplar
• Chapter 2: Microorganisms Friend And Foe

NCERT Exemplar Class 8 Science Solutions for Chapter 2 - Microorganisms Friend and Foe

Ncert exemplar solutions class 8 science chapter 2 – free pdf download.

NCERT Exemplar Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe will assist students in cross-checking their knowledge on various concepts and topics in Microorganisms. Students who are planning to take the annual exam should study this NCERT Exemplar Solutions Class 8 Science thoroughly to understand the concepts from the exam point of view.

The NCERT Exemplar has answers to the questions provided in the NCERT Exemplar book. All the questions provided in exemplar books are solved by the subject experts, and this page has answers to 7 MCQs, 9 very short answer questions, and 11 short answer questions. The chapter Microorganisms: Friend and Foe are about learning what microorganisms are and how they help us to survive. In this chapter, students will learn about different types of microorganisms, like friendly microorganisms and harmful microorganisms. Visit the below link to get a free downloadable PDF.

NCERT Exemplar Class 8 Science Solutions for Chapter 2 – Microorganisms Friend and Foe

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Access Answers to NCERT Exemplar Class 8 Science Chapter 2 – Microorganisms Friend and Foe

Multiple-choice questions.

1. Which of the following reproduces only inside a host cell?

(a) Bacteria

(d) Fungus.

The answer is (b) Virus

Explanation:

The virus is considered as an intermediate between living and non-living. Outside, a host-virus remains inactive. It can perform its life processes and reproduction only when it is inside a host cell.

2. A disease in human beings caused by a virus is _______.

(a) Typhoid

(b) Influenza

(c) Dysentery

(d) Cholera

The answer is (b) Influenza

Typhoid is caused by bacteria Salmonella typhoid.

Dysentery is caused by an amoeba which is a protozoan.

Cholera is caused by Vibrio cholera bacteria.

3. Pathogenic micro-organisms present in host cells are killed by medicines called

(a) Pain killer

(b) Antibodies

(c) Antibiotics

(d) Vaccines

The answer is (b) Antibiotics

• Pain Killers gives relief from pain.
• Antibodies are produced by our immune system which acts and elicit a specific immune reaction.
• Antibiotics that inhibit or kill certain bacteria.
• Vaccines provide acquired immunity against a particular disease.

4. The two micro-organisms which live in symbiotic association in lichens are

(a) Fungus and Protozoa

(b) Alga and Bacteria

(c) Bacteria and Protozoa

(d) Alga and Fungus

The answer is (d) Alga and Fungus

5. The gas released during the preparation of bread is

(b) Carbon dioxide

(c) Nitrogen

(d) Sulphur dioxide

The answer is (b) Carbon dioxide

Carbon-di-oxide is released due to the fermentation process conducted by yeast. CO 2 causes rising of the dough and makes the bread fluffy.

6. The disease caused by a protozoan and spread by an insect is _________.

(b) Malaria

(d) Measles

The answer is (b) Malaria

Malaria is caused by protozoan named Plasmodium vivax which is transmitted by mosquitos. Other options are viral diseases hence they are wrong answers.

7. Paheli dug two pits, A and B, in her garden. In-pit A, she put a polythene bag packed with some agricultural waste. In-pit B, she dumped the same kind of a waste but without packing it in a polythene bag. She then covered both the pits with soil. What did she observe after a month?

(a) Waste in pit A degraded faster than that in pit B.

(b) Waste in pit B degraded faster than that in pit A.

c) Waste in both pits degraded almost equally.

(d) Waste in both pits did not degrade at all.

The answer is (b) Waste in pit B degraded faster than that in pit A.

Waste in pit B degrades faster than waste in pit A because Polythene in pit B is open and receives oxygen for composting whereas polythene in closed in pit A and organisms don’t receive oxygen to compost the waste material in the polythene bag.

Very Short Answer Questions

8. Unscramble the jumbled words underlined in the following statements.

(a) Cells of our body produce santiidobe to fight pathogens.

(b) curbossulite is an air-borne disease caused by a bacterium.

(c) Xanrhat is a dangerous bacterial disease.

(d) Yeasts are used in the wine industry because of their property of meronettinaf.

a. Antibodies

b. Tuberculosis

d. Fermentation

9. Suggest a suitable word for each of the following statements.

(a) Chemicals added to food to prevent the growth of microorganisms.

(b) Nitrogen-fixing microorganism present in the root nodules of legumes.

(c) The agent spreads pathogens from one place to another.

(d) Chemicals which kill or stop the growth of pathogens.

a. Preservatives

b. Rhizobium

c. Carrier/ vector

d. Antibiotics

10. Match the names of scientists given in Column A with the discovery made by them given in Column B.

Column A – Column B

(a) Louis Pasteur – (i) Penicillin

(b) Robert Koch – (ii) anthrax bacterium

(c) Edward Jenner – (iii) Fermentation

(d) Alexander Fleming – (iv) smallpox vaccine

(a) Louis Pasteur – (iii) Fermentation

(c) Edward Jenner – (iv) smallpox vaccine

(d) Alexander Fleming – (i) Penicillin

11. Name one commercial use of yeast

Yeast is used in making bread and they are used in the fermentation of alcohol.

12. Name the process in yeast that converts sugars into alcohol.

Fermentation is the process in yeast that converts sugars into alcohol.

13. In the soil, which nutrient is enriched by blue-green algae (cyanobacteria)?

Blue-green-algae enriches Nitrogen in the soil.

14. Why should we avoid standing close to a tuberculosis patient while he/she is coughing?

Tuberculosis can spread through the air when the infected person coughs. Hence we avoid standing close to a tuberculosis patient while he/she is coughing.

15. Polio drops are not given to children suffering from diarrhoea. Why?

If the children are suffering from diarrhoea oral polio drops will get excreted due to frequent motions. Hence children with diarrhoea are not given with polio drops.

16. Paheli watched her grandmother making mango pickle. After she bottled the pickle, her grandmother poured oil on top of the pickle before closing the lid. Paheli wanted to know why oil was poured? Can you help her understand why?

Oils prevent the attack of bacteria which will help preserve the pickle for a long period of time.

Short Answer Questions

17. Match the microorganisms given in Column A to the group to which they belong in Column B.

(a) Lactobacillus – (i) Algae

(b) Aspergillus – (ii) Protozoa

(c) Spirogyra – (iii) Fungi

(d) Paramecium – (iv) Bacteria

(a) Lactobacillus – (iv) Bacteria

(b) Aspergillus – (iii) Fungi

(c) Spirogyra – (i) Algae

(d) Paramecium – (ii) Protozoa

18. Classify the following into friendly and harmful microorganisms.

Yeast, malarial parasite, Lactobacillus , bread mould, Rhizobium , Bacillus anthracis

19. While returning from the school, Boojho ate chaat from a street hawker. When he reached home, he felt ill and complained of stomach ache and fell ill. What could be the reason?

The probable reason is that the chaat was contaminated by pathogenic microbes due to unhygienic conditions near the shop, or the utensil used for serving could have been contaminated.

The reason may be the contamination of food by pathogenic microbes. Contamination may be due to the unhygienic conditions near the shop or the utensil used to serve the chaat.

20. What will happen to ‘pooris’ and ‘unused kneaded flour’ if they are left in the open for a day or two?

Pooris and unused kneaded flour get spoiled due to microbial activity. Food gets fermented when kept open and it will be spoiled.

21. (a) Name two diseases that are caused by the virus.

(b) Write one important characteristic of the virus.

a. Polio, HIV

b. A virus can reproduce only when it is inside the host cell.

Long Answer Questions

22. Observe the Fig.2.1 and answer the questions that follow.

(a) Write the name of the disease.

(b) Name the causative agent of this disease?

(c) How does the disease spread from one plant to another?

(d) Name any two plant diseases and the microbes that cause them.

a. Yellow vein mosaic of lady’s finger/okra

b. This disease is caused by a virus called Yellow vein mosaic virus.

c. This disease spread from one plant to another by insects.

d. (i) Citrus canker caused by bacteria (ii) Rust of wheat caused by the fungus

23. How do vaccines work?

When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader. The body also remembers how to fight the microbe if it enters again. If dead or weakened microbes are introduced into a healthy body, the body fights and kills the invading bacteria by producing suitable antibodies. The antibodies remain in the body and we are protected from the disease-causing microbes forever. This is how a vaccine works.

24. Observe the set up given in Fig. 2.2 and answer the following questions.

(a) What happens to the sugar solution in A?

(b) Which gas is released in A?

(c) What changes will you observe in B when the released gas passes through it?

a) Yeast ferments sugar to convert it to alcohol and carbon-di-oxide is released.

b) Carbon-di-oxide

c) CO 2 Coverts limewater milky. 25. Observe the Fig.2.3 and answer the following questions.

(a) Name the microorganism and the group to which it belongs.

(b) Name the food item on which the organism grows.

(c) Does it grow well in dry or in moist conditions?

(d) Is it safe to eat infected bread?

a) The image is of bread mould. It is a fungus

b) It grows on moist and stale bread

c) It grows well in moist conditions

d) No, it is not safe to eat infected bread because fungus produces a poisonous substance which will spoil the food.

26. Give reasons for the following.

(a) Fresh milk is boiled before consumption while processed milk stored in packets can be consumed without boiling.

(b) Raw vegetables and fruits are kept in refrigerators whereas jams and pickles can be kept outside.

(c) Farmers prefer to grow beans and peas in nitrogen-deficient soils.

(d) Mosquitoes can be controlled by preventing stagnation of water though they do not live in water. Why?

a) Fresh milk is boiled to kill the harmful microorganisms in the milk. Packed milk is pasteurized hence there is no need to boil the pasteurized milk.

b)Raw vegetables easily get infected by microbes. Hence they are kept in the refrigerator as low temperature inhibits the growth of micro-organisms. In Jams and pickle, there are sugar and salt which acts as preservatives. Hence they do not get infected easily.

c) Beans and peas are leguminous plants which have Rhizobium in their root nodules. Rhizobium fixes atmospheric Nitrogen to enrich the soil and its fertility gets increases.

d) Though mosquitos do not live in water. But they lay their egg and their larvae grow in water. Hence mosquitoes can be controlled by preventing stagnation of water.

27. How can we prevent the following diseases?

(a) Cholera

(b) Typhoid

(c) Hepatitis A

a) Cholera can be prevented by following good personal hygiene and sanitation practices.

b) Typhoid can be prevented by eating properly cooked food, by drinking boiled water and by getting vaccinated against typhoid disease.

c) Hepatitis can be prevented by drinking boiled water and by getting vaccinated.

28. Complete the following cycle given as Fig. 2.4 by filling the blanks (a), (b), (c) (d)

(a) Lightning fixes nitrogen.

(b) Nitrogen-fixing bacteria and blue-green algae fix atmospheric nitrogen.

(c) Nitrogenous waste from excretion and death.

(d) Bacteria turn compounds of nitrogen into gaseous nitrogen.

Topics of NCERT Exemplar for Microorganisms Friend and Foe Class 8 NCERT Solutions

• Microorganisms
• Habitats of Microorganisms
• Microorganisms and us
• Harmful microorganisms
• Food preservation
• Nitrogen fixation
• Nitrogen cycle

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