Final answer:
Osmosis is the diffusion of water through a membrane, influenced by solute concentrations, leading to hypertonic or hypotonic conditions that can shrink or burst cells, while equilibrium is reached in an isotonic solution.
Step-by-step explanation:
Osmosis is the movement of water molecules through a selectively permeable membrane from an area of high water concentration to an area with lower water concentration. A hypertonic solution has a higher concentration of solutes compared to the inside of a cell, causing water to move out of the cell and may lead to the cell shrinking. In contrast, in a hypotonic solution, which has a lower concentration of solutes compared to the cell interior, water enters the cell, which can cause the cell to swell and possibly burst.
Equilibrium is achieved when the concentrations of solutes are equal on both sides of a membrane, resulting in no net water movement; this is called an isotonic solution. Lastly, diffusion is the process of molecules spreading out evenly from an area of higher concentration to an area of lower concentration.