Answer: The lower areas of the Atmosphere have a high temperature through the heats from the ground.
Explanation: High temperature experienced on the Earth surface is majorly caused by heats from the ground ( Earth crust).As a person ascend up to the Toposphere the temperature continues to reduce because because the heat from the ground is reduced as the heights increased.
It has been proven that as a person ascends into the Toposphere the amount of air and pressure reduces this will eventually lead to expansion of the gas particles which will then reduce the temperature.