The atmosphere is an insulating blanket protecting the earth.It softens the intense light and heat of the sun.Its ozone layer in the stratosphere,absorbs the harmful ultra-violet rays from the sun and thus protects the living organisms from extinction.
Significant amounts of oxygen in the atmosphere sustain most life on earth.
The atmosphere burns up objects(like meteors) approaching from space,preventing most of them from reaching the earth.
The atmosphere contains water vapour whose importance is very great.Because,there would be no water on earth without water(in the form of water vapour) in the atmosphere.
The earth's climate is influenced by the troposphere layer(lowest layer) of the atmosphere