What is the definition of endothermic animals?

Endothermic animals are defined as those that maintain a constant body temperature through internal physiological mechanisms. This characteristic allows them to remain active in a variety of environmental conditions, as they can generate heat through metabolic processes to regulate their body temperature.

These animals, commonly referred to as warm-blooded, can adapt to changes in their surroundings more effectively compared to those that rely solely on external sources of heat (which would be ectothermic animals). The ability to maintain a stable internal temperature enables endothermic animals to sustain metabolic activities and remain functional, even in fluctuating environmental temperatures.

The other choices describe aspects of temperature regulation but do not capture the defining feature of endothermic animals specifically, which is their reliance on metabolic processes to generate and maintain their body heat.