Question

1. what are coral reefs primarily formed from?

a) sand and silt
b) coral polyps calcium carbonate
c) seaweed and kelp
d) ocean sediments

Explanation:

Coral reefs are built by coral polyps that secrete calcium carbonate to form their exoskeletons. Over time, these accumulate to form the reef structure.

Answer:

B. Coral polyps' calcium carbonate