Answer:
Because if they don't that would be reckless and they could suffocate and die
Explanation:
I hope that this answers your question :)
Answe
They should pay attention because there is no free oxygen in the sea water since the little dissolved oxygen present in water can't be used for breathing by divers; It can only be used only by aquatic animals. So they need to check how much oxygen they have left so they can go back to the surface.
Explanation:
