Many corals secrete an exoskeleton that builds up to become a coral reef.
An insect has a hard outer covering called an exoskeleton.
Many corals secrete a hard outer covering that builds up to become a coral reef.
Many corals secrete what to form a coral reef?
Options:
a: Chlorophyll
b: salt and water.
c: The area was once underwater
d: Chemical energy
e: aqueous solution
f: Organic compounds
g: gastropod shells
h: hard outer covering