In humans, respiration occurs in the following steps. Arrange these steps in the correct order. Choose the correct answer from the options given below :
- A, B, C, D, E
- C, A, B, E, D
- C, B, E, A, D
- E, A, C, D, B
Answer
(3) C, B, E, A, D
Solution
Air first enters and leaves the lungs by pulmonary ventilation (C).
Gases then diffuse across the alveolar membrane (B) and are carried by blood (E).
Next, O2 and CO2 diffuse between blood and tissues (A), and cells use O2 in cellular respiration (D).
Order: C, B, E, A, D.
Answer: (3)