Which type of coral reef typically forms a circular or continuous barrier surrounding a lagoon, without a central island protruding above the sea surface?

💡 Solution & Explanation

An atoll is a ring-shaped coral reef system that encircles a central lagoon without any prominent landmass rising above the sea surface. Fringing reefs develop directly along coastlines, whereas barrier reefs are separated from the shore by a deep lagoon. These marine formations typically develop on sinking volcanic foundations in tropical oceans.