Pollution is a change in physical, chemical or biological characters of our land and water that may be

(1) Desirable and harmful to human

(2) Desirable and useful to a human

(3) Undesirable and harmful to human

(4) undesirable and useful to a human

Which is the greatest air pollutant these days

(1) Factories

(2) Motor vehicles

(3) Domestic appliances

(4) animals

Removal of the soil by the action of wind and water is known as

(1) Erosion

(2) Fossilization

(3) Leaching

(4) Calcification

Acid rain occurs due to the presence of : 

1. $S{O}_2$ in the atmosphere

2. $N{H}_3$  in the atmosphere

3. $C{O}_2$  in the atmosphere

4. $N_{2}O$  in the atmosphere

Photochemical smog was first observed in -

(1) London

(2) Los Angeles

(3) Paris

(4) Tokyo

An increase in ${\mathrm{CO}}_2$ concentration in the atmosphere will result in : 

1. Adverse effects on natural vegetation.

2. Global warming.

3. Temperature decrease in a global atmosphere.

4. Genetic disorders in plants and animals.

Domestic waste will lead to -

(1) Biodegradable pollution

(2) Nondegradable pollution

(3) Thermal pollution of soil

(4) Air pollution

The major source of BOD in the river Ganga is 

(1) Leaf litter

(2) Fishes

(3) Human waste

(4) Aquatic plants

If a lake is contaminated with DDT, its highest concentration would be found in

(1) Primary consumer

(2) Secondary consumer

(3) Tertiary consumer

(4) None of these

The most harmful air pollutant produced by automobiles is- 

1. ${\mathrm{HNO}}_2$

2. NO

3. ${\mathrm{SO}}_2$

4. CO