JAMB Chemistry 2021 Paper

Concept:Calcium carbonate exists in several natural forms, including rocks and biological materials.Explanation:Calcium trioxocarbonate (IV) is the chemical name for $\mathrm{CaCO}_3$.It occurs abundantly in the earth’s crust as limestone, chalk, and marble.Eggshells are also made almost entirely of $\mathrm{CaCO}_3$ crystals.So all the listed items are forms of calcium carbonate.Answer:D. I, II, III, and IV