Which structures are included in the lower airway?

• A. Nose, Mouth, Pharynx
• B. Trachea, Bronchi, Lungs
• C. Alveoli
• D. Diaphragm

Answer: (B)

The lower airway consists of the passages that carry air down into the lungs and the lungs themselves where gas exchange occurs. The trachea and bronchi are the main conducting airways, and the lungs contain these airways and the air sacs they end in. So listing trachea, bronchi, and lungs covers the components that make up the lower airway.

The other options don’t fit as well because the nose, mouth, and pharynx are part of the upper airway, which handles warming, humidifying, and filtering air before it reaches the lower tract. The diaphragm is a breathing muscle, not an airway. Alveoli are the gas-exchange units within the lungs, but focusing on that single component misses the major conducting pathways down to the lungs.