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JAMB Biology 1993 Question 31

Question 31

Homeostasis

When it is cold, the blood vessels of the skin

  1. A.dilate to increase the amount of blood flowing to the skin
  2. B.constrict to reduce the amount of blood flowing to the skin
  3. C.dilate to reduce the amount of blood flowing to the skin
  4. D.constrict to increase the amount of blood flowing to the skin
Show the answer and explanation

Answer: B (constrict to reduce the amount of blood flowing to the skin)

Explanation

In the cold, skin blood vessels narrow (vasoconstriction) so less warm blood reaches the surface and less heat is lost.