Which solution would be most likely to lead to increased intracellular water?

The reason hypotonic saline is the most likely to lead to increased intracellular water is due to the osmotic principles governing fluid movement in the body. When hypotonic saline is administered, it has a lower concentration of solutes compared to the intracellular fluid. This difference creates an osmotic gradient that facilitates the movement of water into the cells, as water naturally moves from areas of lower solute concentration (hypotonic solution) to areas of higher solute concentration (inside the cells).

As the hypotonic solution is introduced into the extracellular space, the cells will absorb water to achieve osmotic balance. This leads to an increase in intracellular water, which can cause the cells to swell.

In contrast, hypertonic saline would draw water out of the cells, causing dehydration and shrinkage. Isotonic saline maintains the existing osmotic balance between the intracellular and extracellular compartments, leading to no significant change in intracellular water. Colloid solutions primarily work by increasing oncotic pressure in the vascular space and do not directly influence the movement of water into cells. Thus, hypotonic saline is the most effective in promoting increased intracellular water.