Assertion: hard coral | /r/HasProperty | reef builders
Facets:
Source sentences:
text: Hard corals are reef builders and are responsible for the creation of the structure of a coral reef.
text: Hard corals are hermatypes, or reef-building corals, and need tiny algae called zooxanthellae (pronounced zo-zan-THEL-ee) to survive.
text: Hard corals are the building blocks of a reef.