Answer to Question 1
The first step in the evolution of a coral reef is the formation of a fringing reef. These are small reefs that form around an island.
As the island sinks, the fringing reef continues to grow upwards. It is now larger and separated from the main island by a lagoon. The reef is now called a barrier reef.
The third stage occurs as the reef continues to grow up and the island continues to subside. When the island is no longer visible and only a circular reef remains at the surface, an atoll has formed.
Answer to Question 2
C