Question

marine organisms have carbon in their bodies in which of the following forms?
calcium carbonate
pure carbon
carbon dioxide
bicarbonate

Explanation:

Marine organisms, especially those like corals and mollusks, incorporate carbon in the form of calcium carbonate (\(CaCO_3\)) in their shells and skeletons. Pure carbon is not a common form in their bodies in a significant structural way. Carbon dioxide is a gas that can be dissolved in water but is not a major structural form in their bodies. Bicarbonate (\(HCO_3^-\)) is an ion in water but not a form that makes up the body structure of marine organisms in the way calcium carbonate does.

Answer:

calcium carbonate