Environmental Science

Samacheer Book Back Questions And Answers For Science Standard 9 “Environmental Science“

I. Choose the correct answer:
1. All the factors of biosphere which affect the ability of organisms to survive and reproduce are called as _____.
(a) biological factors
(b) abiotic factors
(c) biotic factors
(d) physical factors

2. The ice sheets from the north and south poles and the icecaps on the mountains, get converted into water vapour through the process of _____.
(a) evaporation
(b) condensation
(c) sublimation
(d) infiltration

3. The atmospheric carbon dioxide enters into the plants through the process of _____.
(a) photosynthesis
(b) assimilation
(c) respiration
(d) decomposition

4. Increased amount of _____ in the atmosphere, results in greenhouse effect and global warming.
(a) carbon monoxide
(b) sulphur dioxide
(c) nitrogen dioxide
(d) carbon dioxide

II. Match the following:
1. Microorganism                A. Role played
2. Nitrosomonas                  B. Nitrogen fixation
3. Azotobacter                     C. Ammonification
4. Pseudomonas species      D. Nitrification
5. Putrefying bacteria           E. Denitrification

Answers:
1. A
2. D
3. B
4. E
5. C

III. State whether true or false. If false, correct the statement:
1. Nitrogen is a greenhouse gas.
2. Poorly developed root is an adaptation of mesophytes.
3. Bats are the only mammals that can fly.
4. Earthworms use the remarkable high frequency system called echoes.
5. Aestivation is an adaptation to overcome cold condition.

Answers:
1. False (Carbon dioxide is a greenhouse gas)
2. False (Poorly developed root is an adaptation of Hydrophytes)
3. True
4. False (Bats use the remarkable high frequency system called echoes)
5. False (Aestivation is an adaptation to overcome dry condition)

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