________ are natural or synthetic materials made up of long molecular chains of identical chemical subunits.

• A. Ceramics
• B. Metals
• C. Polymers
• D. Composite

Answer: (C)

Polymers are materials built from long molecular chains formed by repeating units, or monomers. These chains can be natural, like cellulose, starch, proteins, and DNA, or synthetic, such as polyethylene, nylon, and polystyrene. The defining feature is that the same chemical subunit repeats over and over to create a long, chain-like molecule. This structure gives polymers a wide range of properties, like flexibility, light weight, and versatile processing, which is why they’re so common in everyday items.

Ceramics and metals are different in structure: ceramics are inorganic networks that are typically rigid and brittle, and metals consist of atoms arranged in a crystalline lattice with metallic bonding. Composites combine two or more materials to achieve desired properties, but they aren’t defined by long chains of identical subunits.