Is it true Coral reefs form when the calcite skeletons of coral build upon each other?

Yes, coral reefs form when the calcite skeletons of coral build upon each other. Coral polyps are small animals that secrete hard exoskeletons made of calcium carbonate. When a coral polyp dies, its skeleton remains and provides a foundation for new polyps to grow on. Over time, these skeletons can build up to form large coral colonies and eventually, coral reefs. Coral reefs are important ecosystems that provide food and shelter for a variety of marine life.