Final answer:
Airflow is directly related to the pressure gradient and inversely related to resistance, with increased pressure gradients increasing airflow while increased resistance decreases it.
Step-by-step explanation:
Airflow is directly related to the pressure gradient and inversely related to resistance. The correct answer is B. directly, inversely. This means that as the pressure gradient increases, airflow increases; however, as resistance increases, airflow decreases.
The pressure gradient is the driving force that causes air to flow from an area of higher pressure to an area of lower pressure. Flow rate increases with a greater pressure differential. Conversely, airway resistance, which can be caused by factors such as the airway size, slows down the flow of gases. The relationship between airway resistance and pressure changes can be represented by the formula F = ΔP/R, where F is the flow rate, ΔP is the change in pressure, and R is the resistance.