The term polymer is used to describe any long molucular chain made up of individual repeating parts. Waxes are some of the simpler polymers as its monomer (single part) is just a single carbon atom with some hydrogen atoms. The term plastic is not that well defined and is often synonymous with polymer. So it may not be wrong to consider wax a type of plastic. Alothough others may include physical properties in the definition. So wax and rubber may not always be considered plastics.
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