- A Conformers, whose body temperature varies with surroundings
- B Poikilotherms, animals with variable body temperature
- C Homeotherms (regulators)
- D Ectotherms, relying on external heat sources
Correct answer: C. Homeotherms (regulators)
Explanation: Mammals and birds are homeotherms (regulators) that maintain a relatively constant internal body temperature through physiological mechanisms.
Concept context
How organisms interact with abiotic factors and respond to stress, plus population attributes, growth models, and interspecific interactions such as predation, competition, and mutualism.