The flow of fluid or air is inversely proportional to which factor?

The relationship between the flow of fluid or air and resistance is fundamental in understanding fluid dynamics and respiratory physiology. According to the principles of fluid flow, specifically Poiseuille's law, the flow rate of a fluid through a tube or the flow of air through the respiratory system is inversely proportional to the resistance encountered by that flow.

This means that as resistance increases—due to factors like narrowing of airways or increased viscosity—flow decreases. Conversely, if resistance decreases (for example, through bronchodilation in the lungs), flow increases. This principle emphasizes the importance of maintaining low resistance for optimal airflow and fluid transport in various biological systems, including circulation and respiration.

In the context of the other options, pressure influences flow but does not have an inverse relationship; higher pressure typically increases flow rates. Temperature affects the properties of gases and fluids but does not establish an inverse relation with flow. Humidity influences air density and viscosity, but it is not directly characterized by an inverse relationship with flow either.