What describes the passive transport of water across a selectively permeable membrane?

Osmosis specifically refers to the passive transport of water across a selectively permeable membrane. This process occurs when water molecules move from an area of lower solute concentration to an area of higher solute concentration in an attempt to equalize solute concentrations on both sides of the membrane. It is a critical physiological process that helps maintain cellular homeostasis and regulates the internal environment of cells.

Other transport mechanisms such as facilitated diffusion involve the movement of molecules across a membrane via specific transport proteins, but they do not pertain directly to the movement of water. Diffusion describes the general movement of molecules from areas of higher concentration to lower concentration, which applies to solutes rather than water specifically. Bulk transport, on the other hand, encompasses processes like endocytosis and exocytosis that move large quantities of materials into or out of the cell, which is distinct from the selective and passive nature of osmosis in the context of water transport.