This is a large, covalently-bonded molecule that has a repeated structural unit

The correct answer is polymer.

Explanation:

A large macromolecule or molecule, comprising several repeated subunits is considered as a polymer. Because of their varying range of characteristics, both synthetic and natural polymers perform ubiquitous and essential functions in everyday life.

The polymers are of distinct types, that is, it ranges from synthetic plastics like polystyrene to natural polymers like DNA and proteins, which are fundamental to biological activities and composition. Both the natural and synthetic polymers are produced by the process of polymerization of various small molecules known as monomers.

This is a large, covalently-bonded molecule that has a repeated structural unit. This is a complex carbohydrate made from many different sugar molecules joined together. A macromolecule that contains carbon, hydrogen, oxygen, and nitrogen, which is used by the body for growth and repair.