Basic Geography/Atmosphere

The atmosphere is the layer of air surrounding Earth, on which all life depends on. It can be living (biotic) or non-living (abiotic) things. Structure of the atmosphere The atmosphere is divided into four layers: the troposphere, stratosphere, mesosphere and thermosphere, classified by temperature. In each layer, the temperature is either increasing or decreasing as the height above Earth's surface increases. Composition of the troposphere The troposphere consist of a number of different permanent and variable gases. Permanent gases occur in fixed amounts. In this part of the atmosphere is where weather is usually experienced. The permanent gases include: Nitrogen: 78% Oxygen: 21%, the gas humans use for respiration Argon: 1% Carbon dioxide: 0.04%, for plant growth