Step-by-step explanation:
The layers of atmosphere are differentiated on the basis of different temperature gradients.Thus,different layers within the atmosphere are created.
Toposphere is heated from the ground. Thus, with increase in altitude temperature decreases.
In the stratosphere, temperature increases with altitude. The direct heat source for the stratosphere is the Sun. Air in the stratosphere is stable because warmer, less dense air sits over cooler, denser air.
In Mesosphere temperature decreases with altitude. Few gas molecules present in mesosphere absorb sun's radiation.The heat source is the stratosphere below. The mesosphere is extremely cold, especially at its top, about -90°C.
Thermosphere which also contains ionosphere.The density of molecules is so low in here that one gas molecule could easily go upto 1 km before it collides with another molecule. It is so little energy is transferred, the air feels very cold