What is ring shaped islands?

Ring-shaped islands are also known as atolls and are formed due to the submergence of coral reefs. Atolls are mostly found in the Pacific, Indian, and Atlantic oceans. These islands are usually circular or oval-shaped with a lagoon in the center. The circular shape of an atoll is the result of the growth of coral reefs around a submerged volcano. The volcano gradually sinks, leaving behind a circular coral reef around the rim and a lagoon in the center. Atolls are typically low-lying islands and are prone to flooding and erosion. Despite their fragile nature, atolls are home to a diverse range of marine life, making them popular tourist destinations for snorkeling and diving.