On a cold day, the arterioles supplying the capillaries of the skin

  • A. constrict, reducing heat loss from the surface
  • B. dilate widely to warm the skin
  • C. burst under pressure
  • D. stop carrying blood altogether

Explanation

Vasoconstriction keeps warm blood in the core, which is why skin looks pale in the cold. Dilation happens in heat to dump warmth, the opposite response to the opposite stimulus.

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