They count them out of the box.
Some Caribbean islands are coral islands formed from shells and marine animals skeletons.
These islands belong in the older group of Caribbean islands. Aruba, Bonaire, Curacao, Barbuda, Antigua etc. belong to this group. They practically represent a low laying plateaus composed of billions, if not trillions, of shells and marine animals skeletons that are accumulated on the ocean floor.
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The colonies are a natural survival strategy. ... They're always close to water because the swallows build their nests from globs of mud they collect by the beak full.
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