What role does phosphorylation and dephosphorylation play in cell signaling? what role do secondary messengers, such as ca+2 and cyclic amp (camp), play in cell signaling? why are they called secondary messengers? what does cell signaling have to do with homeostasis of cells? how else, besides cell signaling, do cells do to maintain homeostasis? organisms respond to changes in their environment through behavior and physiological feedback mechanisms. give two specific examples of behavior mechanisms and the physiological response(s) of the organism(s).