Which statement describes thermoplastics according to the material?

• A. Every plastic
• B. A subset of plastics that melt and reform
• C. They are metals
• D. They are gases

Answer: (A)

Thermoplastics are a subset of plastics that melt and reform when heated. They soften with heat, can be reshaped, and then harden again as they cool, which lets them be recycled or remolded into new shapes. This behavior comes from their lack of chemical crosslinks; heating increases molecular mobility without undergoing permanent curing. By contrast, thermosetting plastics crosslink during curing and don’t melt cleanly, so they can’t be remolded. Examples like polyethylene and polystyrene illustrate how thermoplastics are processed by melting and molding.