What is the process of transferring water across a cell membrane by osmotic pressure until it is balanced called?

• A. Osmosis
• B. Isotonic Pressure
• C. Diffusion
• D. Filtration

Answer: (A)

Osmosis is the movement of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration, driven by osmotic pressure, until the concentrations on both sides are equal. This matches the idea of water being transferred to balance conditions across the membrane. It differs from diffusion, which is the movement of dissolved substances themselves down their concentration gradient; filtration, which is water movement driven by bulk pressure; and isotonic, which describes a solution with the same solute concentration as the cell rather than the process of water movement.