What is the correct order of airflow in the lower respiratory system starting from the trachea?

In the lower respiratory system, the correct order of airflow starting from the trachea is to first pass through the right and left mainstem bronchi. These bronchi diverge from the trachea and enter each lung, where they then branch into smaller pathways.

Following the mainstem bronchi, the airflow continues into the bronchioles, which are the even smaller air passages that branch from the mainstem bronchi and become progressively narrower. The bronchioles lead to the alveoli, which are tiny air sacs where gas exchange occurs between the air and blood.

Understanding this sequence is critical in studying respiratory function, especially regarding how air travels through the respiratory tract to facilitate oxygen uptake and carbon dioxide expulsion. The other options do not accurately reflect this sequence of airflow, leading to confusion about the structure and function of the respiratory system.