NCERT Class-9 Science Solutions: Chapter 14-Natural Resources Part 2

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Question 8:

Among the given options, which one is not correct for the use of large amount of fertilizers and pesticides?

1. They are eco-friendly

2. They turn the fields barren after some time

3. They adversely affect the useful component from the soil

4. They destroy the soil fertility

Answer: A

Question 9:

The nitrogen molecules present in air can be converted into nitrates and nitrites by

1. A biological process of nitrogen fixing bacteria present in soil

2. A biological process of carbon fixing factor present in soil

3. Any of the industries manufacturing nitrogenous compounds

4. The plants used as cereal crops in field

Answer: A

Question 10:

One of the following processes is not a step involved in the water-cycle operating in nature

1. Evaporation

2. Transpiration

3. Precipitation

4. Photosynthesis

Answer: D

Question 11:

The term “water-pollution” can be defined in several ways. Which of the following statements does not give the correct definition?

1. The addition of undesirable substances to water-bodies

2. The removal of desirable substances from water-bodies

3. A change in pressure of the water-bodies

4. A change in temperature of the water-bodies

Answer: C

Question 12:

Which of the following is not a greenhouse gas?

1. Methane

2. Carbon dioxide

3. Carbon monoxide

4. Ammonia

Answer: D

Question 13:

Which step is not involved in the carbon-cycle?

1. Photosynthesis

2. Transpiration

3. Respiration

4. Burning of fossil fuels

Answer: B

Question 14:

‘Ozone-hole’ means

1. A large sized hole in the ozone layer

2. Thinning of the ozone layer

3. Small holes scattered in the ozone layer

4. Thickening of ozone in the ozone layer

Answer: B