Page 85 - Journeys Through Society-7

4.

The Atmosphere

Get Ready

Label the pie chart showing composition of air along with percentage.

The atmosphere extends more than a thousand The atmosphere contains oxygen and nitrogen which
kilometres above the Earth’s surface. The blanket of are essential for life on Earth. It contains water vapour
air that surrounds the earth is known as the which causes precipitation and influences various
atmosphere. The air is an important life support weather activities on Earth.
system on planet Earth. The ozone layer absorbs the harmful ultraviolet rays of
the Sun and protects the biosphere from their harmful
Importance of the Atmosphere
influence.
The atmosphere acts as a protective layer against
intense heat and cold, thereby moderating Composition of the Atmosphere
temperatures on Earth. Air, which makes up the atmosphere, is a mixture of
It contains carbon dioxide which is used in the process several gases. Nitrogen makes up about 78% and
of photosynthesis by the plants to produce their own oxygen about 21% of the total volume of the
food. atmosphere. Carbon dioxide is released into the air

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