Coral reefs are some of the most diverse ecosystems on Earth. Although th cover le than o percent o the oc floor, th provide ho for ab a qua of a marine species. Reefs are built by tiny animals called corals, which slowly produce hard skeletons that pile up over thousands of years. Many corals also depend on small algae that live inside their bodies and supply them with food. When ocean water becomes too warm, this partnership can break down, and the corals may lose their color and eventually die.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.