THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Answer and Explanation: Trachea-main bronchi-lobar bronchi-segmental bronchi-primary bronchioles-terminal bronchioles-respiratory bronchioles-alveolar ducts-alveoli. As air enters into the trachea, it will pass to the main or primary bronchi.

Detailed explanation-2: -The trachea branches to give rise to two primary (main) bronchii. These then branch successively to give rise in turn to secondary and tertiary bronchii. These then branch to give rise to several orders of progressively smaller airways called bronchioles, the smallest of which are called terminal bronchioles.

Detailed explanation-3: -Answer and Explanation: The structures in order from largest to smallest is B. Bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveoli. Air moves through these airways in this order during inhalation to reach the alveoli, where oxygen participates in gas exchange with the blood.