In science we have been learning about the atmosphere. There are four layers of the atmosphere. First, there is the troposphere where planes and birds and things like that fly. Then there is the stratosphere, on top of that is the mesosphere, and on top of that is the thermosphere. The troposphere is extremely important because it absorbs ozone which is like oxygen, just with 3 oxygen molecules. Without the troposphere it would be way to hot to live.