What type of solution has fewer dissolved particles than blood?

A hypotonic solution has fewer dissolved particles than blood, which accounts for its characteristic of causing cells to swell when exposed to it. This is because the lower concentration of solutes in the hypotonic solution leads to an osmotic movement of water into cells, aiming to equalize the concentration of solutes on both sides of the cell membrane.

In contrast, an isotonic solution has an equal concentration of dissolved particles as blood, meaning cells remain stable without significant swelling or shrinking. A hypertonic solution contains a higher concentration of dissolved particles than blood, leading to water moving out of cells and causing them to shrink. A concentrated solution generally implies a high concentration of solutes, which would not correlate with having fewer dissolved particles than blood. Thus, the definition of these solutions directly supports why a hypotonic solution is the correct answer.