Science
How Well Do You Really Know Coral Reefs?
They're animals, not plants. They support 25% of all marine life. And they're dying.
They're animals, not plants. They support 25% of all marine life. And they're dying.
Coral reefs support roughly 25% of all marine species despite covering less than 1% of the ocean floor — making them the most biodiverse marine ecosystems on Earth and earning them the nickname 'rainforests of the sea.' This quiz covers 50 questions on coral biology, reef ecosystems, and the crisis threatening their survival.
You'll discover why corals are animals (not plants), how the Great Barrier Reef compares to entire continents in biodiversity, the science behind coral bleaching, which everyday products threaten reefs, and the innovative techniques scientists are using to restore damaged ecosystems.
Corals are animals — specifically, they are colonies of tiny polyps related to jellyfish and sea anemones. The confusion arises because they host photosynthetic algae (zooxanthellae) within their tissue, which provide up to 90% of the coral's energy and give reefs their vibrant colors.
Coral bleaching occurs when warming ocean temperatures stress corals, causing them to expel the symbiotic algae living in their tissue. Without these algae, the coral turns white and loses its primary energy source. If temperatures don't drop quickly, the coral starves and dies.
The outlook is concerning — scientists project that even 1.5°C of warming could cause 70-90% of coral reefs to decline. However, some corals show natural heat resistance, and restoration efforts including selective breeding of heat-tolerant strains offer hope. Limiting warming remains the most critical factor.
Last updated: March 2026