Final answer:
The number of primary bronchi matches the number of lungs, with one primary bronchus for each lung - the right and the left. Humans have two lungs; hence there are two primary bronchi.
Step-by-step explanation:
The number of primary bronchi corresponds to the number of lungs, which are the main organs of the respiratory system that the bronchi supply with air. Humans have two primary bronchi, one for each lung. Each lung is anatomically divided into lobes, with the right lung comprising three lobes, and the left lung having two lobes due to the space required for the heart. The primary bronchi do not directly correspond to the number of lobes, as the right primary bronchus branches into three lobar (secondary) bronchi, and the left branches into two.
Therefore, the primary bronchi match with the number of lungs, and not the number of lung lobes, bronchopulmonary segments, or lung lobules. The bronchopulmonary segments are further divisions within the lobes, each receiving air from its own tertiary bronchus. Lastly, the lung lobules are even smaller subdivisions serviced by bronchioles and are not directly related to the primary bronchi either.