Because it has different important things inside to make the cell do it’s job
The reptile's body temperature rises when the external temperature rises. When the temperature drops, so does his body temperature. If a reptile feels cold because the external temperatures have made his blood cold, he'll lie in the sun to warm up. However, if the external temperature is too high, he scurries under a rock, dives in a pool or finds some kind of shade where he can cool down. Reptiles and other animals with ectothermic systems are vulnerable to extreme changes in temperature because they can't control their temperatures internally. They can control their body temperatures only by moving to an environment with a suitable ambient temperature.
50-70%. At the age of 1, percentage is around 65%. In adult men, 60% of their bodies is water. 55% of adult women's weight is water due to fat not holding as much water as lean tissue; fat makes up more of women's bodies than men.
Answer: Negative feedback serves to reduce an excessive response and to keep a variable within the normal range. Negative feedback loops control body temperature and the blood glucose level.
The second and third one I believe