In an isotonic solution, what happens to water movement in and out of a cell?

In an isotonic solution, the concentration of solutes outside the cell is equal to the concentration of solutes inside the cell. As a result, there is no net movement of water in either direction. Water molecules naturally move across the cell membrane due to their kinetic energy, but in an isotonic environment, the rate of water molecules entering the cell is balanced by the rate of water molecules leaving the cell. This dynamic flow maintains equilibrium, which is why the correct answer highlights that water moves freely in both directions without any net movement. The cell remains stable, retaining its shape and function, as there is no excessive influx or efflux of water.