What should divers monitor during a dive to maintain safety?

Monitoring both air supply and depth and time during a dive is critical for ensuring safety and preventing accidents.

Keeping a close eye on air supply is essential because it allows divers to manage their breathing and ensure they have enough air for the entirety of the dive. Running out of air can lead to life-threatening situations, making it crucial for divers to check their tanks frequently and predict when to ascend.

Additionally, monitoring depth and time is vital for avoiding decompression sickness, also known as "the bends." Divers need to be aware of how deep they are and how long they have been underwater to accurately plan their ascent and any necessary safety stops. Staying within predefined limits for time and depth helps to mitigate risks associated with pressure changes in the water.

Therefore, the combination of watching both air supply and monitoring depth and time forms a comprehensive approach to safe diving practices, which justifies that the correct response includes both aspects for optimal safety.