All plastics are polymers, but not all polymers are plastics. The term plastics usually refers to synthetic polymers. Most plastics derive from oil. Monomers, the building blocks used in the synthesis of polymers, are in fact normally obtained by chemically transforming the light fractions of oil.
Natural polymers, such as proteins and DNA, which are spontaneously synthesized by living organisms, are not considered plastics.
Different types of plastics have different chemical and physical properties. However, they normally share many general properties, such as: