The total mass of air surrounding the earth, from the uppermost thermosphere down to the troposphere

Answer

Atmosphere

Explanation

The Atmosphere is what surrounds the Earth in form f layers of gases. The layers of the atmosphere are; the troposphere, stratosphere, mesosphere and the exosphere. Oxygen present in the atmosphere facilitate human survival on earth though nitrogen makes up most of the atmosphere with a 78%.The gases help in absorption of UV rays and in warming the Earth through heat retention