Why would a red blood cell
burst when placed in a
solution of pure water?
a. the solutes rush into the cell.
b. a red blood cell would not burst if
placed in distilled water.
c. the water rushes into the cell.

RBC burst when placed in pure water , Ans C -The water rushes into the cell. Cell swells and burst.

Explanation:

This can be understand by understanding OSMOSIS

      Movement of water molecule from its higher concentration to its lower concentration through a semipermeable membrane is called OSMOSIS.

If cell is placed in any solution in which solute concentration is higher than inside the cell (HYPERTONIC SOLUTION), means water content in cell  is higher then outside environment. Then the water molecule will flow from cell to the outer medium. Water molecule movement continues till concentration of solutes reaches same both in cell as well as in medium.

IF cell is placed in any solution having solute concentration lower than inside   the cell. In this solution water content will be higher and solute concentration will be low (HYPOTONIC SOLUTION). Water movement will be inside the cell from the outer environment. As the result Cell swells and ultimately burst because of excess water content.

IF cell is placed in ISOTONIC SOLUTION, where concentration is same both  in cell and outer environment, No movement of water molecules takes place.

where is the diagram?

if you insert the diagram ill be able to you