Final answer:
The component not part of the lower airway is the Vocal cords (D). They are located in the larynx, part of the upper respiratory system, whereas the lower airway includes the trachea, bronchi, bronchioles, and alveoli.
Step-by-step explanation:
The component that is NOT part of the lower airway is D) Vocal cords.
The lower airway consists of the trachea, bronchi, bronchioles, and alveoli. The trachea is a long tube that extends down to the chest, leading to the lungs. Inside the lungs, the trachea divides into the right and left bronchi, which contain cartilage to maintain their shape. These bronchi further branch out into smaller tubes called bronchioles, which lead to the alveoli, where gas exchange occurs. The mucus in the bronchi helps trap particles, and cilia line the bronchi to sweep these away.
The vocal cords, however, are located in the larynx, which is part of the upper respiratory system and not the lower respiratory system. The main function of the vocal cords is to produce sound.