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).

What is a difference between systemic and pulmonary circulation? a. systemic circulation carries oxygenated blood to the lungs and pulmonary circulation carries deoxygenated blood to the body. b. systemic circulation carries deoxygenated blood to the lungs and pulmonary circulation carries oxygenated blood to the body. c. systemic circulation carries deoxygenated blood to the body and pulmonary circulation carries oxygenated blood to the lungs. d. systemic circulation carries oxygenated blood to the body and pulmonary circulation carries deoxygenated blood to the lungs.