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WAEC Biology 2015 Question 15

Question 15

Transport in Animals

Blood pressure is higher in the arteries as a result of

  1. A.stress.
  2. B.contraction and relaxation.
  3. C.blockage in the arteries.
  4. D.presence of valves.
Show the answer and explanation

Answer: B (contraction and relaxation.)

Explanation

Each contraction of the ventricles forces blood into the arteries under high pressure, and the arteries' elastic walls recoil as the heart relaxes. This is why arterial pressure is high.