One Mark Questions Answers

ENVIRONMENTAL SCIENCE

TEXT BOOK EXCERCISES

 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

[Answer: (c) biotic 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

[Answer: (c) sublimation]

3. The atmospheric carbon dioxide enters into the plants through the process of _{――― .}

(a) photosynthesis

(b) assimilation

(c) respiration

(d) decomposition

[ Answer: (a) photosynthesis]

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

[Answer: (d) carbon dioxide]

II. Match the following:

1.

Microorganism - Role played

Nitrosomonas - Nitrogen fixation

Azotobacter - Ammonification

Pseudomonas species - Nitrification

Putrefying bacteria - Denitrification

Answer:

Microorganism - Role played

Nitrosomonas - Nitrification

Azotobacter - Nitrogen fixation

Pseudomonas species - Denitrification

Putrefying bacteria - Ammonification

III. State whether true or false. If false, correct the statement :

1. Nitrogen is a greenhouse gas.

Answer: False.

Correct statement: Carbon dioxide is a greenhouse gas.

2. Poorly developed root is an adaptation of mesophytes.

Answer: False.

Correct statement: Poorly developed root is an adaptation of Hydrophtes.

3. Bats are the only mammals that can fly.

Answer: True.

4. Earthworms use the remarkable high frequency system called echoes.

Answer: False.

Correct statement: Bats use the remarkable high frequency system called echoes.

5. Aestivation is an adaptation to overcome cold condition.

Answer: False.

Correct statement: Aestivation is an adaptation to overcome dry condition.

IV. Give reason for the following.

1. Roots grow very deep and reach the layers where water is available. Which type of plants develop the above adaptation? Why?

Anwser: Xerophytes have well developed roots.

Reason: They grow in dry habitat where water is scarcely available.

2. Why streamlined bodies and presence of setae is considered as adaptations of earthworm?

Anwser:

1. Streamlined bodies of earthworm helps to live in narrow burrows underground and for easy penetration into the soil.

2. Setae helps earthworm to move through the soil and provide anchor in the burrows.

3. Why is it impossible for all farmers to construct farm ponds in their fields?

Anwser:

1. Farm ponds reduce water flow to other tanks and ponds situated in lower-lying areas.

2. Ponds occupy a large portion of farmer's lands.