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WAEC Biology 2009 Question 15

Question 15

Transport in Animals

The reason why the flow of blood through the capillaries is very slow is

  1. A.because the walls of capillaries are very thin.
  2. B.to avoid high blood pressure.
  3. C.to ensure that the individual does not get dizzy.
  4. D.to allow adequate time for exchange of materials.
Show the answer and explanation

Answer: D (to allow adequate time for exchange of materials.)

Explanation

Slow flow in capillaries gives time for oxygen, food and wastes to diffuse between the blood and the tissues.