Osmosis

Osmosis is the passive movement of water molecules through a selectively permeable membrane, from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration). This process does not require energy, as it is a type of diffusion. Osmosis is critical for maintaining proper fluid balance in cells and organisms, allowing water to move into or out of cells based on the concentration of solutes inside and outside the cell. Thus, osmosis involves the movement of water molecules from high to low concentration.