What is endothermy in mammals and why is it significant?

• A. Endothermy is the production of external heat to regulate body temperature.
• B. Endothermy is heat exchange with the environment to keep body temperature steady.
• C. Endothermy is internal heat production to maintain stable body temperature; allows high metabolism and activity in varied environments.
• D. Endothermy is a behavioral strategy of basking to stay warm.

Answer: (C)

Endothermy is the ability of mammals to generate most of their body heat internally through metabolic processes. This internal heat production keeps a relatively constant body temperature even when the surrounding environment changes, which is why mammals are considered warm-blooded or homeothermic. Maintaining a stable temperature supports high metabolic rates, fueling active movement, digestion, and brain function across a wide range of environments. This physiological trait grants mammals greater ecological flexibility, allowing them to stay active in cold conditions and during varying climates. The other statements describe external heat sources, heat exchange with the environment, or a behavioral tactic like basking, none of which define endothermy.