What is true about plastic in the context of materials?

Plastic is indeed a polymer, which means it is composed of long chains of repeating molecular units called monomers. This characteristic allows plastics to have properties that can be tailored for various uses, such as flexibility, durability, and resistance to moisture.

In contrast, a natural material typically refers to substances that occur in nature and are not significantly altered by human processes, whereas plastics are primarily synthetic, manufactured from petrochemicals. The statement that plastic does not have a defined structure is misleading, as many plastics can have specific structures that contribute to their physical properties.

Therefore, describing plastic as not being a polymer is inaccurate; plastics are fundamentally defined by their polymeric nature, which is central to their use and behavior as materials.