NCERT Class VIII Science Solutions: Chapter 2-Microorganisms: Friend and Foe Part 1

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Question 1:

Which of the following reproduces only inside a host cell?

  1. Bacteria

  2. Virus

  3. Amoeba

  4. Fungus.

Answer: B

Question 2:

A disease in human beings caused by virus is _______.

  1. Typhoid

  2. Influenza

  3. Dysentry

  4. Cholera

Answer: B

Image of different virus for diffrent disease

Different Virus for Diffrent Disease

Question 3:

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

  1. Pain killer

  2. Antibodies

  3. Antibiotics

  4. Vaccines

Answer: C

Question 4:

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

  1. Fungus and protozoa

  2. Alga and bacteria

  3. Bacteria and protozoa

  4. Algae and fungus

Answer: D

Image of Algae and fungus

Image of Algae and Fungus

Question 5:

The gas released during the preparation of bread is

  1. Oxygen

  2. Carbon dioxide

  3. Nitrogen

  4. Sulphur dioxide

Answer: B

Question 6:

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

  1. Dengue

  2. Malaria

  3. Polio

  4. Measles

Answer: B

Question 7:

Paheli dug two pits, A and B, in her garden. In pit A, she put a polytene 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?

  1. Waste in pit A degraded faster than that in pit B.

  2. Waste in pit B degraded faster than that in pit A.

  3. Waste in both pits degraded almost equally.

  4. Waste in both pits did not degrade at all.

Answer: B

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