Which structures constitute the lower airway according to the material?

• A. Trachea, bronchi and bronchioles and lungs
• B. Nasal cavity and pharynx
• C. Larynx and vocal cords
• D. Alveoli only

Answer: (A)

The lower airway includes the main conducting airways from the windpipe down through the branching tubes, plus the lung structures where gas exchange happens. So listing the trachea, bronchi and bronchioles along with the lungs captures both the air-conducting pathways and the site of gas exchange, which is why this option is the best match. The nasal cavity and pharynx belong to the upper airway, the larynx is usually considered part of the upper airway as well, and alveoli by themselves don’t represent the full lower-airway pathway.