General biology laboratory 101: what is the reasons for why the volume of the cell in hypertonic  solution has reduced, and why it increased in the hypotonic  solution?

In a hypertonic solution, the solvent inside of the cell rushes out, causing the cell to shrivel and lose volume. In a hypotonic solution, the solvent rushes into the cell, causing it to expand and gain volume. This happens because of diffusion, which explains that molecules in the solvent will move from an area of high concentration to an area of low concentration.