What best defines osmosis?

Osmosis is best defined as the diffusion 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, aiming to equalize solute concentrations on both sides of the membrane. This movement is crucial for maintaining cell turgor and overall homeostasis within organisms.

In a selectively permeable membrane, some substances can pass through while others cannot, which is a key aspect of osmosis. The focus on water as the diffusing substance distinguishes osmosis from other forms of diffusion, which can involve various solutes. The specificity of osmosis to water makes it a critical process for biological functions, such as nutrient absorption and waste removal in cells.