Tropopause is the boundary between the troposphere and stratosphere.
Explanation:
Tropopause marks the transition region between troposphere and stratosphere.
As we move up from the Earths surface , the temperature gets colder but when we reach the tropopause the temperature becomes constant and the temperature does not fall further.
It is at a height of about 9Km at the polar region while at a height of 17 Km at the equitorial region.
