Isotonic is significant to homeostasis how?

It helps homeostasis, by maintaining the shape of a cell depending on how much solute is outside of the cell and how much water is inside the cell, in an isotonic solution the size of the cell stays the same because the amount of water inside the cell is the exact same percentage of solute outside of the cell.

The answer is ATP                          

It make sthe cell function good and i got the asnwer wrong