1. exosphere
the outermost layer of the atmosphere
2. ionosphere
a sub-layer of the thermosphere where the atmosphere begins to blend into space
3. mesosphere
the second layer of the atmosphere, found above the troposphere
4. ozone
a form of oxygen having three atoms of oxygen making up the molecule (o3)
5. stratosphere
a sub-layer of thermosphere made of charged ions and free electrons
6. thermosphere
the layer of the atmosphere nearest the earth
7. troposphere
the layer of the atmosphere just above the stratosphere