atmosphere earth's layers
the life on earth exists because of the atmosphere that surrounds it. it is a body of air that contains oxygen without which life on the earth is not possible. gases like nitrogen (78%) , oxygen (just under 21%) are the main constituents of the air. rare gases like helium, neon, argon, krypton, radon, xenon and carbon dioxide make the rest of it.
the Troposphere is where we breath in and is also referred to as the lower atmosphere. of all the atmospheric layers,this is the most closest to the earth .