Answer: ERV and RV.
- A TV and IRV
- B IRV and ERV
- C TV and RV
- D ERV and RV
Correct answer: D. ERV and RV
Explanation: Functional residual capacity (FRC) is the air remaining in the lungs after a normal expiration and equals expiratory reserve volume plus residual volume.
The S-shaped (sigmoid) curve reflects cooperative binding between Hb's four O₂ sites; the Bohr effect shifts the whole curve to the right under conditions found in actively respiring tissue (more CO₂, more acid, more heat), making haemoglobin release oxygen more readily exactly where it's needed.
Concept context
The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.