Explain what would happen if you put an animal cell into a hypotonic
solution. Why does this differ from what would happen if you put a
plant cell into a hypotonic solution?

The brief text under "Hypotonic" on this page should help:

http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20100/Bio%20100%20Lectures/Membranes/membrane.htm

For long answer, try wikipedia.com but take note that the information
presented there may or may not be correct.

The definition of a hypotonic solution is that there's less solute
outside the cell than inside the cell.  Therefore, water will migrate
from outside to inside the cell, engorging the cell.  In cases where
there is a significant difference between amounts of solute, the cell
may explode and die.

An easy way to see how this happens is to take slices of fresh, live
potatos, or any other living cell and immerse them in distilled water
(a hypotonic solution).  The potato slice will noticeably become
longer after a few hours of emersion in the water.

in a solution that is 'hypotonic' (that is, contains a lower
concentration of solute compared to the cell) an animal cell will
swell as water moves by osmosis down its concentration gradient INTO
the cell. given enough of a difference the cell will eventually burst.
an plant cell on the other hand will most always have a cell wall
which will allow water to enter up to the limit set by the size of the
cell wall, this is turgidity (and why your plants wilt if they haven't
been watered in a while).