Which of the following emergency equipment should always be available at dive sites?

Having first aid kits and oxygen supplies readily available at dive sites is essential for ensuring the safety and well-being of divers. In the event of an emergency, such as an injury or a diving-related medical issue like decompression sickness, immediate access to first aid equipment can make a significant difference in the outcome. Oxygen supplies are particularly critical, as they are the first line of treatment for certain diving emergencies, including barotrauma and hypoxia.

This emphasis on having these supplies aligns with best practices in dive safety, as they enable quick response to incidents that can arise during diving operations. The presence of well-stocked first aid kits and oxygen equipment helps ensure that divers can receive prompt attention in case of emergencies, thus mitigating potential risks associated with diving activities.