What is the primary purpose of a secondary regulator during a dive?

The primary purpose of a secondary regulator, also known as an octopus, is to provide an additional source of air for a buddy or for the diver in emergency situations. In the event that a diver runs out of air or if another diver is in distress, the secondary regulator allows for air sharing, ensuring that both divers can safely ascend to the surface or reach a safer depth. This is a critical safety feature in diving, as it helps prevent panic and enables a controlled response to an emergency.

While options involving increased breathability, monitoring oxygen levels, or replacing the primary regulator may relate to diving equipment, they do not align with the primary function of the secondary regulator, which is specifically designed for air sharing. The focus on emergency air supply highlights the importance of preparedness and mutual assistance during dives, which is a key aspect of diver safety.