Multiple choice general knowledge Which is found in egg shells? CaCl CaNo3 CaCO3 CaSO4+NaCl Reveal answer Fill a bubble to check yourself C Correct answer Explanation Calcium carbonate (CaCO3) is the main chemical compound that provides the rigid structure of bird eggshells. The other options represent different calcium salts like chloride, nitrate, or sulfate, which do not constitute the shell material.