What do many corals secrete that build up to become a coral reef?
an external framework The area was once underwater that material's properties bioaerosols water dust after too much water received oxygen
A B C D E F G H
An exoskeleton is an external framework.
many corals secrete an external framework that builds up to become a coral reef
What do many corals secrete that build up to become a coral reef? (A) an external framework (B) The area was once underwater (C) that material's properties (D) bioaerosols (E) water (F) dust (G) after too much water received (H) oxygen