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NCERT solutions Science Class 8 chapter 2 Microorganisms : Friend and Foe

Chapters

NCERT Science Class 8

Science Textbook For Class 8

Chapter 2 - Microorganisms : Friend and Foe

Pages 29 - 30

Fill in the blanks:

Microorganisms can be seen with the help of a _________

Q 1.1 | Page 29

Fill in the blanks:

Blue green algae fix _________ directly from air to enhance fertility of soil

Q 1.2 | Page 29

Fill in the blanks:

Alcohol is produced with the help of _________

Q 1.3 | Page 29

Fill in the blanks:

Cholera is caused by _________.

Q 1.4 | Page 29

Tick the correct answer:

Yeast is used in the production of

(1) sugar

(2) alcohol

(3) hydrochloric acid

(4) oxygen

Q 2.1 | Page 29

Tick the correct answer:

The following is an antibiotic

(1) Sodium bicarbonate

(2) Streptomycin

(3) Alcohol

(4) Yeast

Q 2.2 | Page 29

Tick the correct answer:

Carrier of malaria-causing protozoan is

(1) female Anopheles mosquito

(2) cockroach

(3) housefly

(4) butterfly

Q 2.3 | Page 29

Tick the correct answer:

The most common carrier of communicable diseases is

(1) ant

(2) housefly

(3) dragonfly

(4) spider

Q 2.4 | Page 29

Tick the correct answer:

The bread or idli dough rises because of

(1) heat

(2) grinding

(3) growth of yeast cells

(4) kneading

Q 2.5 | Page 29

Tick the correct answer:

The process of conversion of sugar into alcohol is called

(1) nitrogen fixation

(2) moulding

(3) fermentation

(4) infection

Q 2.6 | Page 29

Match the organisms in Column I with their action in Column II.

  Column I   Column II
1 Bacteria a Fixing Nitrogen
2 Rhizobium b Setting of curd
3 Lactobacillus c Baking of bread
4 Yeast d Causing Malaria
5 A protozoan e Causing Cholera
6 A Virus f Causing AIDS
    g Producing antibodies
Q 3 | Page 29

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

Q 4 | Page 29

What are the major groups of microorganisms?

Q 5 | Page 30

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

Q 6 | Page 30

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

Q 7 | Page 30

Write a short paragraph on the harms caused by microorganisms.

Q 8 | Page 30

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

Q 9 | Page 30

NCERT Science Class 8

Science Textbook For Class 8
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