Final answer:
An isotonic solution has the same osmolarity as the cell, resulting in no net movement of water into or out of the cell.
Step-by-step explanation:
An isotonic solution has the same osmolarity as the cell.
Osmolarity describes the total solute concentration of a solution. In an isotonic solution, the extracellular fluid has the same osmolarity as the cell, resulting in no net movement of water into or out of the cell.
For example, a red blood cell in an isotonic solution will maintain its normal volume and shape.