Diffusion of water into or out of a cell is called

a) solubility

b) endocytosis

c) osmosis

d) diffusion

The best answer would be C. Most cells have a semipermeable membrane and it is through this semi permeable membrane that water molecules and other particle move in or out of the cell. Osmosis is defined as movement of solvent or water from the area of its higher concentration to the area where it is less concentrated, through a semi - permeable membrane. Osmosis involves the movement of solvent molecules only. A solvent is a substance, usually a liquid which dissolves a solute. Water is an excellent solvent.