Answer:
Homeostasis.
Step-by-step explanation:
Homeostasis may be defined as the mechanism by which living organisms maintain their internal body temperature. The homeostasis is important in exothermic animals.
Jim sweats in hot summer day so that body can maintain the internal temperature by reducing excessive heat and makes the body cool by sweating. As he went in the air-conditioned room he stops sweating because the body internal and external temperature is cool enough.Hence, the body temperature is maintained by the homeostasis.
Thus, the correct answer is option (B).