Hypotonic osmosis. The water equally distributed through their body. It is hypotonic because water is going into their cells.
I believe that the answer is frequency. :)
Very simple. At rest, you have a number of bpm. After exercise, the heart can't return abruptly to the rest speed, and it keeps a faster rate for a while.
A cell spends 10-20% of its time in Mitosis.
If this is wrong...sorry :)