Which statement is true regarding thermoregulation?

• A. An ectotherm such as a lizard does not maintain a fairly constant body temperature.
• B. Endotherms must always maintain a fairly constant body temperature to survive.
• C. In furry animals, raised hairs keep the animal cooler than lowered hairs.
• D. A dilated blood vessel conserves more heat than a constricted one.
• E. Ectotherms generally do not conserve body heat as effectively as do marine mammals.

Answer: (E)

Verified step by step guidance

1. Understand the concept of thermoregulation: Thermoregulation is the process by which animals maintain their body temperature within certain boundaries, even when the surrounding temperature is different.
2. Differentiate between ectotherms and endotherms: Ectotherms rely on external environmental conditions to regulate their body temperature, while endotherms generate heat metabolically to maintain a constant body temperature.
3. Analyze the statement about ectotherms: Ectotherms, such as lizards, do not maintain a constant body temperature; instead, their body temperature fluctuates with the environment.
4. Consider the role of fur in thermoregulation: In furry animals, raised hairs trap more air and provide insulation, keeping the animal warmer, not cooler.
5. Evaluate the function of blood vessels in heat conservation: Dilated blood vessels increase blood flow to the skin, facilitating heat loss, while constricted vessels reduce blood flow to conserve heat.