Sinkholes are formed by the actions of acid rain plant roots ocean water groundwater

Sinkholes form when groundwater breaks down limestone causing the earth to cave in often forming a pond or body of water as the underground stream and rain continues to fill the hole

the answer is

c. parental

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.