Final answer:
Hypothermia occurs when body temperature drops below normal, and hyperthermia occurs when body temperature rises above normal.
Step-by-step explanation:
The serious health situation that occurs when the body is unable to regulate its temperature is called hypothermia when the body temperature drops below normal and hyperthermia when the body temperature rises above normal. Hypothermia can occur in extremely cold conditions, causing confusion, lethargy, and eventually loss of consciousness and death. Hyperthermia can occur in extremely hot conditions, leading to heat stroke and potentially life-threatening complications.