When a patient comes to a hospital with severe dehydration, doctors will give them an IV filled with a salt-water solution called saline, which is isotonic with
the body's blood cells.
Why is the patient not given pure water?

The red blood cells could burst.

Explanation:

If they are given pure water, the IV fluid will be hypotonic to the blood cells. That means water will end the red blood cells by osmosis, from a high concentration outside to a lower concentration inside.

This will result in the red blood cells becoming swollen and even potential  bursting.

for 8 am not sure maybe yes?

for 9 if it is asking if the male is more or less it would be less

hope i even just a little : )