Final answer:
A hypotonic solution causes cells to swell as water moves into the cells, potentially leading to the cells bursting if the water intake is excessive.
Step-by-step explanation:
When our skin cells become 'bloated' with water after staying in water for an extended period, the type of tonicity causing cells to become oversized is known as hypotonic.
In a hypotonic solution, the concentration of solutes is lower outside the cells than inside. This results in water moving into the cell via osmosis, leading to cells swelling. If this swelling goes unchecked, it can cause cells to burst, a process known as hemolysis for red blood cells.
By contrast, in an isotonic solution, the concentration of solutes is equal inside and outside the cell, so there is no net water movement, and the cell size remains stable. In hypertonic solutions, water moves out of the cell, leading to cell shrinkage, or crenation, when it comes to red blood cells.