The cell membrane gateway system you are looking for is called <span>Sodium Potassium Pump.</span>
I could be wrong I’m not very smart but I think it’s b
The answer would be "the boiling and freezing points of water."
Functions of cell surface Receptors .
most ligands responsible for cell-cell signaling ( including neurotransmitters, peptide, hormones, and growth factors) bind to receptors on the surface of their target cells.
