Which statement best describes the difference between osmosis and diffusion in passive transport?

• A. Osmosis is the movement of any molecules from low to high concentration, while diffusion is only the movement of water across a membrane.
• B. Diffusion occurs only across selectively permeable membranes, while osmosis can occur in any space without a membrane.
• C. Diffusion is the movement of solute particles down their concentration gradient, while osmosis is the diffusion of water across a selectively permeable membrane toward higher solute concentration.
• D. Diffusion requires ATP to move molecules across a membrane, while osmosis is always passive and occurs only in animal cells.

Answer: (C)