An Atoll
A Reef
A Bommy (Australian slang).
coral
A coral atoll is a ring-shaped coral reef or island found in warm, tropical oceans. They are formed from the accumulation of coral skeletons on the rims of submerged volcanic islands over thousands of years. Atolls typically enclose a lagoon in their center.
An ocean current?
Surface currents
Yes, they live in temperate tropical waters. They also love to reside in coral reefs, sea grass and mangrove forsts beneath the surface of the ocean. You are welcome!
yes, it is possible for a volcano to lie beneath the ocean surface.
Coral atoll are tiny sea animals that live in shallow water, but when reefs form the new coral grow over the skeleton of the old. As the ocean crust beneath the volcano sinks, the coral sinks with it, and the new coral continues to form on top of the old. Eventually, coral covers the whole volcano. It can survive with the ocean waves bringing in new food and more marine life.
Red
yes
yes
tunami
About 70% of the Earth's surface is covered by water.