Carbon Atom: This is an element with atomic number 6. It's known for its ability to form stable covalent bonds with other elements, including itself, making it a key component in many molecules necessary for life.
Oxygen Atom: An element with atomic number 8. Oxygen readily forms compounds by reaction with almost any other element.
Molecule:A group of two or more atoms held together by chemical bonds. In this case, CO2 is a molecule composed of one carbon atom and two oxygen atoms.