Membrane proteins are among the most important proteins biologically because they allow cells to communicate with their environments. In humans, they determine whether the immune system recognizes the cell as foreign or not and they are the targets of most pharmaceuticals. In all organisms, membrane proteins are responsible for other functions as well. Select which function determines when and if cell division takes place.
A) regulating salt balance.
B) controlling water intake.
C) activation of growth hormones.
D) the control cell adhesion to form tissues.