The middle layer of the atmosphere, stratosphere layer next to layer 4 and 40 km further there is very little ozone layer temperature is reduced accordingly. When moving upwards to find molecules of gas in the form of io building, O2, NO, the temperature in this layer + less remaining-100 oC level.
90 kilometers from the Earth surface height operating temperature constant, this area is that the mesopause, which is the floor joints during the next class.
Mesosphere layer helps protect the world from meteors each meteorite into this layer will be burnt to salvage most of the rest are no bar.