Other kinds of tools are corers, which have long tubes that bring up bits of mud and sand from the bottom of the sea. Electronic sounding tools send back echoes from the ocean floor. From these echoes, scientists can learn about how deep the ocean is in different places. These tools are very important. However, the observations made by real live divers are even more useful.
Some divers use scuba gear for short trips beneath the surface.
Underwater vehicles called submersibles make it possible for divers to go deeper in the ocean and stay there longer. In this way, divers can study changes in the ocean floor. They can also study plant and animal life in the sea. These answers will be the main topics of your outline. This is how you would write them in your outline.