Question

what are monomers best described as?
individual units or building blocks
indivisible particles
complex structures

Explanation:

In biology (a subfield of Natural Science), monomers are the individual units or building blocks that combine to form polymers. "Indivisible particles" is incorrect as monomers can be broken down, and "complex structures" is wrong because monomers are simple units, not complex. So the correct description is "individual units or building blocks".

Answer:

A. individual units or building blocks