Class 8 Science – Chapter 2
Microorganisms: Friend and Foe
Worksheet

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✍️ Section A: Fill in the Blanks

1. Microorganisms that can be seen only with a microscope are called __________.
2. __________ is used in making bread and cakes.
3. Malaria is caused by a __________.
4. The process of heating milk to kill harmful germs is called __________.
5. __________ bacteria help in fixing nitrogen in soil.

📝 Section B: True or False

1. All microorganisms are harmful. ( ______ )
2. Viruses can reproduce only inside a host. ( ______ )
3. Salt is used as a food preservative. ( ______ )
4. Cholera is caused by a virus. ( ______ )
5. Algae can prepare their own food. ( ______ )

❓ Section C: Very Short Answer

1. Name one disease caused by bacteria.
2. Which microorganism is used to make curd?
3. Name any one food preservation method.
4. Which microorganism causes malaria?

📘 Section D: Short Answer

1. How are microorganisms useful to us?
2. What is pasteurization?
3. Write two ways by which diseases spread.
4. How do microorganisms spoil food?

🧠 Section E: Long Answer

1. Explain different methods of food preservation.
2. Describe the harmful effects of microorganisms.

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