Final answer:
The U.S Coast Guard-approved pyrotechnic VDS include flares and smoke signals for distress signaling at sea.
Step-by-step explanation:
The U.S. Coast Guard-approved pyrotechnic VDS (Visual Distress Signals) include flares and smoke signals that are used to signal distress at sea. Flares are ignited pyrotechnic devices that produce bright light to attract attention, while smoke signals release dense smoke clouds to provide a visual indication of distress.
Flares are typically handheld or parachute flares that can be seen from far distances, while smoke signals are used to mark the location of a distressed vessel. Both types of VDS are important safety equipment for maritime emergencies and complying with Coast Guard regulations.