Zoology - Breathing and Exchange of Gases Question with Solution | TestHub

Option (3) is the answer, because the respiration involves the following stages: 1. Breathing or pulmonary ventilation by which atmospheric air is drawn in and ${\mathrm{CO}}_2$ rich alveolar air is released out. 2. Diffusion of gases $({\mathrm{O}}_2$ and ${\mathrm{CO}}_2)$ across alveolar membrane. 3. Transport of gases by the blood. 4. Diffusion of ${\mathrm{O}}_2$ and ${\mathrm{CO}}_2$ between blood and tissue. 5. Utilisation of ${\mathrm{O}}_2$ by the cells for catabolic reactions and resultant release of ${\mathrm{CO}}_2$ Rest of options (1), (2) and (4) are not the answers because these steps are not arranged in the correct sequence.