Final answer:
Polymers of carbon alone do not solely comprise plastics; plastics are primarily composed of carbon and hydrogen. Synthetic plastics are made from monomers like ethylene, and while natural polymers exist, synthetic ones have a wide range of applications.
Step-by-step explanation:
The assertion that polymers of the substance carbon make up plastic is false. Many plastic materials are indeed organic polymers and they do contain carbon, but they also include other elements, primarily hydrogen. Synthetic plastics such as polyethylene, polyvinyl chloride (PVC), and polystyrene are made up of long chains of carbon and hydrogen atoms, originating from monomers like ethylene (CH₂=CH₂).
Natural polymers also exist, such as starch and proteins. Starch is a polymer of sugar residues, and proteins are polymers of amino acids. However, when it comes to synthetic polymers used to make plastics, the carbon atoms form the backbone of the molecule, which is then modified with different functional groups to obtain properties suited for various applications. For instance, polyethylene can vary in density and melting point depending on the number and length of its branched chains.