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JAMB Biology 1982 Question 38

Question 38

Respiration

Which of the following statements is TRUE of inhalation of air by man?

  1. A.The ribs are not raised
  2. B.Diaphragm is raised
  3. C.Intercostal muscles relax
  4. D.Pressure of the thoracic cavity increases
  5. E.Size of thoracic cavity increases.
Show the answer and explanation

Answer: E (Size of thoracic cavity increases.)

Explanation

During breathing in, the ribs rise and the diaphragm flattens, so the chest cavity gets bigger and pressure falls.