Carbon chains form skeletons list the types of skeletons that can be formed

From the carbon chains form skeletons, the forms of skeletons that can be made are: carbon skeletons which differ in length, the skeleton double bonds which can differ in location, skeletons maybe split for unbranched and some are settled in rings. In addition to carbon and the molecular diversity of life, a hydrocarbon is a hydrophobic molecules containing of only carbon and hydrogen such as benzene and methane. Isotope is an substitute system of the same element comprising equal number of protons but a dissimilar number of neutrons in the nucleus and thus some different properties while an isomer is an substitute system of similar compound with the similar formula but may vary in organization of atoms in the molecule and thus may vary in properties. 

Carbon dioxide is the correct answer