Final answer:
Hypothermia is defined as a very low body temperature resulting from prolonged exposure to cold. It is a serious condition that affects the body's metabolic processes and, in controlled medical situations, can be used to protect organs during surgery.
Step-by-step explanation:
Based on the context provided, the correct definition for hypothermia is a very low body temperature. Prolonged exposure to cold can lead to this serious condition, where the body's core temperature drops below the normal range necessary for metabolic processes to function correctly. When the core temperature begins to significantly drop, red blood cells lose their ability to release oxygen, which can lead to confusion, lethargy, and potentially loss of consciousness or death. In medical settings, controlled hypothermia is sometimes used during surgeries to reduce metabolic rates and protect organs, by intentionally cooling the body within a specific temperature range.