What is osmosis?

• A. Diffusion
• B. Osmosis
• C. Endocytosis
• D. Filtration

Answer: (B)

Osmosis is the movement of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration, driven by the goal of equalizing solute concentrations on both sides.

This differs from diffusion, which involves solute particles moving from higher to lower concentration, not specifically the movement of water. Endocytosis is the active uptake of large particles into a cell via vesicles, and filtration is movement of water and solutes driven by pressure differences. In practical terms, osmotic flow of water helps maintain cell turgor and fluid balance in tissues, such as water moving into plant cells in a hypotonic environment or out of cells in a hypertonic one.