Final answer:
Two solutions with the same solute concentration are isotonic, meaning there is no net water movement across a cell membrane; in contrast, hypertonic and hypotonic solutions have higher and lower solute concentrations, respectively.
Step-by-step explanation:
If two solutions have the same concentration of solutes, they are known as isotonic. This is because 'iso' means equal or the same. In an isotonic solution, the amount of water entering a cell is the same as the amount leaving the cell since there is no net movement of water due to the equal solute concentration inside and outside the cell.
Hypertonic solutions have a higher solute concentration compared to another solution, leading to water leaving the cell to balance the solute concentrations. On the other hand, hypotonic solutions have a lower solute concentration than the inside of the cell, which causes water to move into the cell.