The answer is c02 regulation, the carbonic acid bicarbonate buffer regulation, the H+ regulation and gas exchange. The following regulations are all completed through the circulatory, excretory and respiratory systems which is part of one huge function that is called homeostasis. Homeostasis is the predisposition to repel alteration in order to uphold a even comparatively constant internal situation.
A cell membrane protects a cell from it's surroundings. The cell membrane controls the movement of substances from the outside and inside of cells and organelles.