Which term describes an animal that maintains its body temperature through metabolic heat?

• A. Endotherm
• B. Ectotherm
• C. Gill Membranes
• D. Gas Exchange

Answer: (A)

Internal heat production to regulate body temperature defines endothermy. An animal that maintains its body temperature through metabolic heat generates heat internally and uses physiological mechanisms like metabolism, insulation, and blood flow adjustments to keep a relatively stable temperature despite environmental changes. This constant internal warmth supports steady enzyme activity and metabolic processes, which is especially useful in marine settings where temperatures can vary with depth or season. By contrast, organisms that rely on external heat sources—warming up or cooling down with the surroundings—are ectotherms, and their body temperatures fluctuate with the environment. Terms like gill membranes or gas exchange relate to respiration, not temperature regulation, so they don’t describe how body heat is managed.