Final answer:
SCUBA is the independent air supply system used by divers, standing for Self-Contained Underwater Breathing Apparatus, allowing divers to breathe underwater and manage risks like decompression sickness.
Step-by-step explanation:
The respirator with an independent air supply that is used by underwater divers is known as SCUBA, which stands for Self-Contained Underwater Breathing Apparatus. Scuba divers use compressed air or mixtures of gases such as nitrox to breathe while they explore underwater environments. Whether diving at the Great Barrier Reef or the Caribbean, scuba divers must be knowledgeable about important concepts such as buoyancy, pressure equalization, and the management of the amount of time they spend underwater to safely enjoy their activity and to avoid the risks associated with pressurized gases in the body, also referred to as decompression sickness or 'the bends.'