Because water goes through your systems and makes you survive. They can live with water forever.
A diet that consist highly of fruits with lots of vitamin c and vegetables along with coconut water and pomegranate juice can help maintain body heat and not lead to it over heating and of course lots of cold water. Milk with a bit of honey could also help.
The answer is, 43 km/hr . Speed is,

So we will divide the given distance to the given time, so :
Answer: Tempature is the independent Variable, Activity is the dependent
Explanation:
independent variables are what you manipulate in an experiement and dependent variable are what happens after you change the independent variable