Concept:Air moves from the larger airways to smaller air sacs in the lungs.Explanation:Air enters the trachea, then branches into the bronchi.The bronchi divide into smaller bronchioles.Bronchioles end in alveoli, where gas exchange occurs.Therefore, the correct order is trachea → bronchi → bronchioles → alveoli.Answer:A. trachea → bronchi → bronchioles → alveoli