Answer:
The answer is "homeostasis."
Explanation:
Homeostasis <em>is the dynamic state of equilibrium which allows an organism to have a stable internal condition while resisting natural changes in the external environment. </em>Having a stable condition allows the organism to function normally in order to survive. <u><em>This also allows the body to maintain certain levels of oxygen, pH and core body temperature.</em></u>
<em>In the case above, although the temperature outside is 31 degrees, John maintains a temperature of 98 degrees, which is higher than the outside environment, in order for his cells, tissues and organs to function normally.</em>
If his body fails to achieve a homeostatic condition, then he'd die.