Lung Regions: Conducting vs. Respiratory Zones

Steps:

• Recall trachea and bronchioles line with ciliated epithelium and mucus to trap and remove dust/particles from inhaled air.
• Note alveoli feature thin walls and dense capillary networks for O2/CO2 diffusion during gas exchange.
• Eliminate options misassigning alveoli to cleaning or bronchioles/trachea to exchange.
• Select D for accurate functional separation despite phrasing.

Why D is correct:

• Trachea and bronchioles conduct and clean air via ciliary action (conducting zone definition), while alveoli specialize in gas exchange per respiratory zone physiology.

Why the others are wrong:

• A: Wrongly assigns cleaning to alveoli (gas exchange site) and exchange to non-diffusion areas.
• B: Limits cleaning correctly but restricts exchange to bronchioles, ignoring alveoli.
• C: Matches cleaning but option D includes redundant "bronchiole" per table's cell types.

Final answer: D