Final answer:
The hose through which air flows in an SCBA or supplied air respirator is termed a breathing tube, serving as a crucial channel for air delivery to facilitate respiration.
Step-by-step explanation:
The hose through which air flows, either within a Self-Contained Breathing Apparatus (SCBA) or from an outside source to a supplied air respirator, is termed a breathing tube. This conduit is essential for ensuring that clean air is delivered to the wearer in environments where the surrounding air is unsafe to breathe. The breathing tube serves as a critical channel for air delivery, enabling either external or internal respiration depending on the specific type of respiratory aid being used. For instance, in the case of a SCBA, it facilitates pulmonary ventilation by providing a breathable air source that is independent of the surrounding atmosphere.