The importance of atmosphere of the earth are:-
=> The presence of the atmosphere plays a significant role in the water cycle. It facilitates the formation of clouds which remains suspended until they are heavy enough to pour down on the earth as rain,hail or snow.
=>Protects the life forms of the earth from the harmful UV rays of the sun.The presence of the ozone layer does this by reflecting the UV rays of the sun.
=> It keeps the temperature of the earth constant so that it is suitable to support life.
=> It protects the earth from smaller meteors.
=> Contains N_2 ,O_2 and other gases which are necessary to support the life form on the earth.
=>Facilitates combustion and without the atmosphere combustion is not possible.
Here is the structure of the atmosphere:-
