The correct answer that would best complete the given statement above would be the first option. Coral reefs are built by a small organism called a polyp. The polyp creates the structure of the coral reef by building a CUP out of a calcium carbonate. The skeletons of these tiny corals s<span>ecreted by the lower portion of the polyp. Hope this answer helps.</span>
Hey?! Not sure how to respond to this?
It is sensors :) i hope this helped you :)