Which of the following do the excretory, digestive, and respiratory system have in common?

A) they are present only in animals with backbones

B) they contain specialized surfaces for exchange with the environment

C) they work independently, without any control by the nervous system

D) they enable the animal to absorb needed materials from its environment

E) they are isolated from the animals internal environment

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.

high growth (apex)