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Coral Reefs - National Geographic Society
Coral reef - Wikipedia
Coral reef | Description, Geochemistry, Origins, & Threats
What is a coral reef? | Natural History Museum
Coral reef ecosystems - National Oceanic and Atmospheric Administration
Coral reef facts for kids! - National Geographic Kids
What Are Coral Reefs? | Live Science
Coral Reefs 101 | National Geographic - YouTube
Coral - National Geographic Society
Coral Reefs | UNEP - UN Environment Programme