Your body will only be able to function and maintain it's homeostasis at a constant stable temperature of 98 degree's farenheit. It will usually only be able to take a min of 96 or a max of 102. Usually at hitting those max/min, the body will have begun to loose it's ability to mantain that temperature and it could then start beginning a downward spiral of Hypo- and hyper- Thermia, which is very dangerous.
The answer is Blood Chemistries.
The first one is correct, because your skin is always the first thing anything comes incontact with.
Doctors would say that it is C.
A. Is also greatly needed to keep oneself safe
