AIR AROUND US

The gas present in the maximum amount in the air is

• nitrogen

• carbon dioxide

• argon

• oxygen

The gas released by green plants during photosynthesis is

• nitrogen

• oxygen

• carbon dioxide

• water vapour

For burning of fuels ,which of the following gases is necessary?

• oxygen

• nitrogen

• carbon dioxide

• hydrogen

Water is found in the air in the form of

• dust

• water vapour

• ice

• carbon

Balance of oxygen and carbon dioxide in air is maintained by ----------

• plants only

• animals only

• both plants and animals

• moving vechiles

The layer of ozone gas protect us from

• sunlight

• ultraviolet rays

• carbon monoxide

• microorganism

What is the percentage of oxygen in air ?

• 30

• 21

• 28

• 78

The layer of air surrounds the earth is called ----

• atmosphere

• wind

• ozone layer

• nitrogen

The amount of water vapour present in air is referred to us

• humidity

• wind

• atmosphere

The contamination of air by undesirable substance

• air pollution

• wind

• water pollution

• none of these