In a cold environment, which physiological response helps conserve body heat?

In a cold environment, which physiological response helps conserve body heat?

• A. When you are cold, you have less melatonin.
• B. In a cold environment, blood vessels in your skin constrict to save heat.
• C. If your skin looks pink in warm weather, it is likely because you have mild sunburn.
• D. In cold weather, surface capillaries dilate and make the skin appear whitish.

Answer: (B)

When the body is in a cold environment, it tries to minimize heat loss by keeping blood away from the skin. This happens through vasoconstriction of the skin’s blood vessels, which reduces blood flow to the surface and preserves heat in the body’s core. That makes the option describing skin vessels constricting in the cold the best choice. The other statements don’t explain heat conservation: melatonin is tied to sleep-wake cycles, not temperature regulation; pink skin in warm weather relates to vasodilation or sun exposure, not conserving heat; and dilation of surface capillaries would increase heat loss, not prevent it.

When the body is in a cold environment, it tries to minimize heat loss by keeping blood away from the skin. This happens through vasoconstriction of the skin’s blood vessels, which reduces blood flow to the surface and preserves heat in the body’s core.

That makes the option describing skin vessels constricting in the cold the best choice. The other statements don’t explain heat conservation: melatonin is tied to sleep-wake cycles, not temperature regulation; pink skin in warm weather relates to vasodilation or sun exposure, not conserving heat; and dilation of surface capillaries would increase heat loss, not prevent it.