Final answer:
Smaller airways have less net resistance than larger airways due to the smaller diameter forcing more collisions of air molecules with the airway walls. Airway branching increases the total cross-sectional area and reduces resistance, enabling easier flow of air and efficient gas exchange in the lungs.
Step-by-step explanation:
The resistance in airways is influenced by the size of the airway. Smaller airways have less net resistance compared to larger airways. This is because a smaller tubular diameter forces air through a smaller space, causing more collisions of air molecules with the walls of the airways. As a result, it becomes harder for air to flow through smaller airways compared to larger ones.
This tells us about airway branching in the lungs. Each branching of larger airways into smaller airways increases the total cross-sectional area of the airway tubes. This increase in cross-sectional area reduces the resistance, allowing for easier flow of air. It also allows for more efficient gas exchange in the alveoli, as air velocity decreases in smaller airways.