Acid rain is due to an increase in the atmospheric concentration of : 

1. Ozone, and dust

2. $C{O}_{\mathrm{2,}}$ and CO

3. $S{O}_{\mathrm{3,}}$ and CO

4 $S{O}_{\mathrm{2,}}$ and $N{O}_2$

Soil erosion can be prevented by : 

1. Overgrazing

2. Removal of vegetation

3. Afforestation (Plantation)

4. Increasing bird population

... is not a greenhouse gas :-
1. Hydrogen
2. Carbon dioxide
3. Methane
4. Nitrous oxide or $N_{2}O$

The ozone layer of the upper atmosphere is being destroyed by : 

1. Sulphur dioxide

2. Carbon dioxide

3. Chlorofluorocarbon

4. Smog

If a lake is contaminated with DDT, it's highest concentration would be found in :

1. Primary consumer

2. Secondary consumer

3. Tertiary consumer

4. None of the above.

Domestic waste will lead to : 

1. Biodegradable pollution

2. Nondegradable pollution

3. Thermal pollution of soil

4. Air pollution

If water pollution continues at its present rate, it will eventually :

1. Stop the water cycle.

2. Prevent precipitation.

3. Make oxygen molecules unavailable to water plants.

4. Make nitrate molecules unavailable to water plants.

Pollution can be controlled by-

1. Sewage treatment.

2. Checking atomic blasts.

3. Manufacturing electrically operated vehicles.

4. All of the above.

The main air pollutant among the following is : 

1. CO

2. $C{O}_2$

3. $N_2$

4. Sulphur

The gas that damages the ozone layer is -

1. CFCs 

2. CO₂

3. CH₄ 

4. SO₂