Hypothermia occurs when a. there's a dangerously low level of vitamin b in the body. b. a person exercises outdoors in extreme heat. c. a low internal body temperature interferes with the body's ability to regulate vital processes. d. a person's fat stores become depleted.

Hypothermia occurs when a low internal temperature interferes with the body's ability to regulate vital processes. The answer is option C. Hypothermia occurs when there is too much heat loss after being exposed to low temperatures for a long period of time. The body is unable to regain heat because heat sources are not sufficient.