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Microorganisms: Friend and Foe Practice
Solve chapter-level practice questions for Microorganisms: Friend and Foe with reveal-only solutions and quick revision support.
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Practice Set 1 — Groups and Useful Roles
Types of microbes, fermentation, medicines, and soil fertility.
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Practice Set 2 — Harmful Microbes and Preservation
Pathogens, carriers, food spoilage, and methods of preservation.
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Quick Q&A Before You Revise
Are all microorganisms harmful?
No. Many are extremely useful — they make curd and bread, produce antibiotics and alcohol, decompose waste, and fix nitrogen in the soil. Only some are pathogens.
Why don't antibiotics work against the common cold?
The common cold is caused by a virus, and antibiotics act only on bacteria and fungi. Viral infections are prevented by vaccines and are usually managed by rest and symptomatic treatment.
Why does food kept in a refrigerator last longer?
Low temperature slows down the growth and reproduction of the microorganisms that spoil food, so spoilage is delayed (though not stopped completely).
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