Complex sentence: Brain coral is a common name given to genera of coral which are characterized by the spheroid shape of their colonies, and from the grooves and channels on their surface, which resemble the folds on the surface of the human brain.
Split into simpler sentences: Brain coral is a common name given to several genera of coral which are characterized by the spheroid shape of their colonies. The corals get their common name from their overall shape and from the grooves and channels on their surface, which resemble the folds on the surface of the human brain.