1, plastic

orthopedics

2. Plastic

Plastic, plastic, plastic products and plastic extension materials have different parts of speech:

Plastic. Used as adjectives and noun parts of speech. The adjective is plastic/plastic. The noun is plastic products/plastics. But generally speaking, it is more of an adjective.

Plastic is just a noun, which can be translated into plastic surgery, plastic, plastic products and so on.

These spoons are made of plastic. The spoon is made of plastic.

Many things are made of plastic. Many things are made of plastic.