Which structure is part of the lower airway?

Which structure is part of the lower airway?

• A. Trachea
• B. Larynx
• C. Alveolus
• D. Bronchus

Answer: (D)

Airflow in the lower airway is carried by the passages that move air from the trachea into the lungs and toward the regions where gas exchange happens. The structure inside the lungs that branches from the trachea and distributes air to each lung area is the bronchus. It serves as the main conducting passage within the lungs after the trachea, making it a clear component of the lower airway. The alveolus, by contrast, is where gas exchange occurs, not a conducting airway, and the larynx sits in the upper airway. So the bronchus is the best choice for a structure that is part of the lower airway.

Airflow in the lower airway is carried by the passages that move air from the trachea into the lungs and toward the regions where gas exchange happens. The structure inside the lungs that branches from the trachea and distributes air to each lung area is the bronchus. It serves as the main conducting passage within the lungs after the trachea, making it a clear component of the lower airway. The alveolus, by contrast, is where gas exchange occurs, not a conducting airway, and the larynx sits in the upper airway. So the bronchus is the best choice for a structure that is part of the lower airway.