MCQ
The figure shows a diagrammatic view of human respiratory system with labels $A, B, C$ and $D$. Select the option which gives correct identification and main function and / or characteristic.
- ✓$C$ - Alveoli - Thin walled vascular bag like structures for exchange of gases.
- B$D$ - Lower end of lungs - Diaphragm pulls it down during inspiration.
- C$A$ - Trachea - Long tube supported by complete cartilaginous rings for conducting inspired air.
- D$B$ - Pleural membrane - Surround ribs on both sides to provide cushion against rubbing.