What does a regulator control in a mine's airway?

A regulator in a mine's airway is primarily responsible for the distribution of air by regulating flow resistance. This is crucial for maintaining effective ventilation throughout the mine, as it ensures that fresh air is delivered to different areas where workers are present, and that stale or contaminated air is removed efficiently. By adjusting the flow resistance, the regulator can increase or decrease the volume of air moving through specific sections of the airway, thus optimizing airflow to meet the needs of the mine's operations and the safety of its workers.

While the other choices touch upon important aspects of air management in a mining environment, they do not specifically define the role of a regulator. Temperature and pressure can certainly affect air quality and flow, but a regulator does not control these parameters directly. Instead, its main function is to adjust how air is distributed and how much air reaches different parts of the mine, making the control of flow resistance the correct focus.