Temperature. The “greenhouse effect,” without which the Earth would be freezing.
it protects oxygen and essential gases to be in the biosphere
and protects us from uv rays which can cause skin cancer
the atmosphere block harful rays from the sun. the ozone layers which lies in the stratosphere 11 to 50 km from earth surface ,block out harmful forms of radiation .
and the oxygen within our atmosphere is essentiall for life
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