Trace the route of air from the nares to an alveolus. Name subdivisions of organs where applicable, and differentiate between conducting and respiratory zone structures. (a) Why is it important that...

Trace the route of air from the nares to an alveolus. Name subdivisions of organs where applicable, and differentiate between conducting and respiratory zone structures.

(a) Why is it important that the trachea is reinforced with cartilage rings?

(b) Why is it advantageous that the rings are incomplete posteriorly?