a mid ocean ringe
ocean ridge
A mid ocean ridge
seamount
yes
mid ocean ridges
An undersea volcano is a large mountain underneath the waters that when erupted it forms a new island.
Mid-ocean ridges
atoll
miss singh eats curry
Undersea mountain range with a steep, narrow valley along its center.
The dolphin needs to be in Atlantica. If not, something's wrong. The dolphin is in Undersea Valley I believe it's called, and the Undersea Gorge.