Polymers are formed by joining several units called monomers. what does the term monomer refer to? a) a unit made up of several compounds. b) a unit made up of several atoms. c) a unit made up of several molecules.

The answer is B) A unit made up of several atoms

Let's distinguish all terms:
- Atom is the smallest constituent of an element.
- Molecule is formed when two or more atoms bind chemically together.
- Compound is a molecule consisting of at least two elements.
- Monomer is a molecule made up of several atoms (for example, glucose is made up of carbon, hydrogen and oxygen).
- Polymer is a large molecule formed by joining several monomers (for example, starch consists of many glucose monomers).