State the full forms of LPG and CNG.

Define the following:

(a) Respiration

(b) Photosynthesis

(c) Combustion.

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?