ANATOMY

Detailed explanation-1: -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.

Detailed explanation-2: -The largest airway structure is the trachea. This branches into two smaller bronchi, which enter the left and right lung and bifurcate further into smaller bronchioles. The bronchioles give way into the smallest structures of the lung, the tiny grape-like clusters of alveoli.

Detailed explanation-3: -The trachea (windpipe) is the largest airway. The trachea branches into two smaller airways: the left and right mainstem [or main] bronchi. Each lung is divided into sections (lobes): three in the right lung and two in the left lung.

Detailed explanation-4: -Pathway of air: nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)