In a depressurization or smoke scenario, what does an oxygen mask provide?

• A. Oxygen supply
• B. Breathable oxygen
• C. Cooling air
• D. Communications

Answer: (B)

When cabin air is unsafe—due to depressurization or smoke—you need gas that you can actually breathe. The oxygen mask provides a regulated flow of breathable oxygen from a dedicated source, so you can maintain adequate oxygen levels for your brain and body while the aircraft’s environment becomes unsafe. This isn’t about cooling the air or enabling communications; those functions aren’t what you rely on during an oxygen emergency. The key idea is that the mask delivers oxygen that is suitable for respiration, which is why “breathable oxygen” is the best description.