In an isotonic solution, the concentration of solutes is the same inside and outside the cell. This means there is no net movement of water across the cell membrane. Here's what happens:

* No net water movement: Water molecules move in and out of the cell at equal rates, so there is no overall change in the cell's volume.

* Cell maintains its shape: The cell will not swell or shrink, maintaining its normal shape and function.

* Equilibrium: The cell is in a state of equilibrium with the surrounding environment.

In essence, a cell in an isotonic solution is in a comfortable, stable state.

This is the ideal environment for most cells, as it allows them to function properly without being stressed by changes in water content.