What is the movement of water through a semipermeable membrane from an area of higher concentration to lower concentration called?

The movement of water through a semipermeable membrane from an area of higher concentration to lower concentration is referred to as osmosis. This process specifically involves the passive transport of water molecules and does not require energy. In a solution, water will naturally move toward the area where there is a lower concentration of water (or a higher concentration of solute) in order to achieve equilibrium.

This is a critical concept in biology and is paramount in maintaining proper cell function, as cells rely on osmotic gradients to transport nutrients and waste products. Osmosis is distinct from diffusion, which involves the movement of solute molecules, and does not involve energy expenditure like active transport does. Facilitated diffusion, on the other hand, refers to the process of moving substances across a membrane with the help of transport proteins but is not specific to water. Thus, osmosis accurately describes the selective movement of water through semipermeable membranes, making it the correct answer in this scenario.