What is the ocean floor like?

It has similar elevations and depressions. Mountains, valleys, plateaus on land, also exist underwater. Many tropical islands are simply "underwater mountains" that have their highest peaks above sea level.

If you ever look at an oceanic map of sea depths, and compare it to one of land elevations, you will see striking similarities!

Basically, there are mountains, volcano's, gorges, and cliffs underwater just like that you would find on land, also fault lines, such as the ring of fire is both on land and under water, and just like there is a jet stream of air, there are also streams of hot and cold water currents. And of course, it has living things.