Which features describe the MK-16 Mod 1 Underwater Breathing Apparatus?

• A. No bubbles; electronically driven; 3 oxygen sensors monitor breathing and can auto add O2; diving to 300 feet
• B. Bubble-producing; manually driven; 2 sensors; diving to 100 feet
• C. No bubbles; manually driven; 1 sensor; diving to 200 feet
• D. Bubbles produced; electronically driven; 4 sensors; diving to 400 feet

Answer: (A)

The MK-16 Mod 1 is a closed-circuit rebreather, so you breathe gas that has been recycled rather than expelled as bubbles. This setup is managed by an electronic control system, not by hand-only adjustments, which means the unit can actively monitor you as you breathe and automatically add oxygen to maintain a safe breathing mix. Multiple oxygen sensors provide redundancy and ensure the partial pressure of oxygen stays within safe limits, with the system capable of adjusting O2 automatically as you change depth. That combination—no bubbles, electronic control, multiple O2 sensors with automatic O2 addition, and a depth rating around 300 feet—matches the MK-16 Mod 1’s design and use. The other descriptions describe open-circuit or manually controlled systems, fewer sensors, or deeper depths that don’t align with how the MK-16 Mod 1 operates.