Question

multiple - choice question
what is a monomer?
all the pieces together / like a giant tower
a building block / one unit of a macromolecule
rewatch

Explanation:

A monomer is defined as a single unit that can join together with other monomers to form a polymer (macromolecule). It's like a building block. The option "All the pieces together / like a giant tower" would be more representative of a polymer (the whole structure made of monomers), not a monomer itself.

Answer:

A building block / one unit of a macromolecule