What does the model suggest about a mechanism for regulating ph in an organism?

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. 

Yes he thought they should be left to chance why, because he thought that was the best thing to do