NCERT Class VIII Science Solutions: Chapter 2-Microorganisms: Friend and Foe Part 1 (For CBSE, ICSE, IAS, NET, NRA 2022)

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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

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

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