Final answer:
CO2 will contain both oxygen-16 and oxygen-18 isotopes.
Step-by-step explanation:
Oxygen-18 will contain some of the oxygen-16 that was part of the molecular structure of the material. Both oxygen-16 and oxygen-18 are isotopes of oxygen, which means they have the same number of protons but different numbers of neutrons.
Isotopes can exist in the same material, and when CO2 is formed, it can contain both oxygen-16 and oxygen-18. The relative abundance of these isotopes in CO2 depends on the isotopic composition of the original material.