Give two uses of the following components present in air:

(a) oxygen

(b) nitrogen

(c) carbon dioxide

(d) water vapour

How is air useful to:

(a) water boats

(b) agriculture

(c) windmills

(d) scooters and cars?

Give reason:

Aquatic animals and plants are able to survive in water.

Give reason:

A burning candle stops burning if covered with a glass tumbler.