Coral islands are landforms created from coral reefs, which are structures made of calcium carbonate produced by tiny marine animals called coral polyps. Over time, these reefs can accumulate sand and other materials, forming islands. Coral islands are typically found in tropical and subtropical regions, where warm, shallow waters support coral growth. These islands often feature unique ecosystems, including diverse marine life and specific plant species adapted to sandy, salty environments. Atolls, a type of coral island, are ring-shaped and encircle a lagoon. Coral islands are important for biodiversity and can also provide habitats for various species, including birds and marine animals.