write this in a short sentence
Diffusion is the process by which molecules move from an area of high concentration to an area of low concentration until equilibrium is reached. In the context of a hypotonic solution, the concentration of solutes outside the cell is lower than inside the cell, causing water to move into the cell. In a hypertonic solution, the concentration of solutes outside the cell is higher than inside the cell, causing water to move out of the cell. Equilibrium is reached when the concentration of molecules is the same inside and outside the cell.