approximately 115 days
Human red blood cells (RBC), after differentiating from erythroblasts in the bone marrow, are released into the blood and survive in the circulation for approximately 115 days.
It is surrounded by it's environment.
That would be the independent variable :)
B: They occur more quickly than reactions without enzymes
By the ligand receptors on the surface of the cell membrane. How do transport proteins make it easier for certain molecules to diffuse across a membrane.
the binding of a signaling molecule, or ligand, to its receiving molecule, or receptor.
