Reef builder Crossword Clue

 The answer to the crossword clue "Reef builder" is coral. Corals are marine invertebrates that secrete calcium carbonate to form a hard skeleton. These skeletons can accumulate over time to form reefs, which are important ecosystems that provide food and shelter for a variety of marine life.

The word "coral" can also refer to the colorful, hard structures that corals form. These structures are made up of many individual polyps, which are tiny animals that are related to jellyfish. The polyps secrete the calcium carbonate that forms the coral skeleton.

There are many different types of corals, and they can be found in a variety of habitats around the world. Coral reefs are most common in warm, shallow waters, but they can also be found in deeper waters and in colder climates.

Coral reefs are important ecosystems that provide food and shelter for a variety of marine life. They also help to protect coastlines from erosion. However, coral reefs are threatened by a variety of factors, including climate change, pollution, and overfishing.

I hope this helps! Let me know if you have any other questions.