What method can be used to measure the progress of a dive?

The method of measuring the progress of a dive using light distance is significant because visibility can play an essential role in assessing the diver's position and progress within a cavern. As divers navigate underwater environments, the clarity and reach of light can indicate how far they have traveled from their entry point or guide them through complex passages.

Utilizing light distance helps divers remain aware of their surroundings and aids in judging how deep they are within the cavern, which is vital for maintaining situational awareness and ensuring safety. The perception of light can also provide cues about the proximity to the exit or significant landmarks within the cave, which is crucial in an environment where familiar visual references may be lacking.

In contrast, while other methods like depth measurement and descent rate are important for managing ascent and descent phases, they do not directly represent the diver's overall progress within the cavern system in terms of navigating towards or away from exits or areas of potential danger. Warmth assessment, although it can inform divers about changes in the environment, is less useful compared to light distance in tracking how far the diver has moved within the cave system.