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Plants need Nitrogen to grow. During photosynthesis, plants use carbon

dioxide to make their food and give out oxygen.

Find It What happens if nitrogen is not present in air?
Out

Nitrogen and oxygen make

up about 99% of the air. The Nitrogen - 78%
Oxygen - 21%
remaining is made up of small Other Gases - >1%
Argon - >1%
amounts of carbon dioxide and Carbon Dioxide - 0.04%

other gases.
Composition of air
Air also contains water in the form of water vapour. It is the gaseous form

of air. The heat of the Sun causes the water in lakes, rivers, seas and oceans

to evaporate into water vapour.

When this water vapour cools, it condenses back into water and falls as

rain.

How is the air when you walk into a park or a garden?

The air is clean and we breathe fresh air.

How is the air on a busy road?

Vehicles emit smoke and when we breathe it,

we feel tired and our eyes burn. Sometimes this

smoke causes breathing problems too.

Vehicles releasing smoke
Think &
Answer Is air present in space ? How do astronauts
breathe in space?

Why does this happen?

This is because the smoke contains lot of dust and harmful substances.
Air also contains germs in it. Presence of all such harmful substances in

air makes it unclean. We get unwell when we breathe this air. To keep

healthy, it is necessary to breathe clean air.

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