They are called fringing reefs. They grow directly from shore and form borders along the shoreline.
When a fringing reef continues to grow upward from a volcanic island that has sunk entirely below the sea level, an atoll is formed. Atolls are usually circular or oval in shape, with an open lagoon in the center.
The fringing reef is the most common type of coral reef. They however tend to be very sensitive to human induced pollution in the water and are easily destroyed by such.
The Earth's true shape is called: A Oblate Spheroid. It might just look like a regular circle, but it's not. It's actually a Oblate Spheroid.
I know this because I did some research online.
Hope I helped!
- Debbie
El animal marino está dormido encima de la roca.
Rock layers form when settlements build up over time they usually have to go through pressure and compaction/cementation before this happens