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.
Function of an enzyme is to lower reaction's activation energy and to increase speed of a reaction, but to make it happen, enzyme and substrate must fit spatially. The shape of an enzyme is essential to make enzyme-substrate complex - if active site of an enzyme doesn't fit to substrate, there won't be a enzyme-catalised reaction.
Diffusion and osmosis to get the minerals in and the pholem uses diffusion to transport all parts of the plant body