A monomer is defined as

• A. A molecule that cannot bond
• B. A molecule that is able to bond in long chains
• C. A large piece of polymer
• D. A solvent

Answer: (B)

A monomer is a small molecule that can bond to other molecules to form long chains, called polymers. The idea is that many of these building blocks join together through chemical bonds to create a larger, repeating structure. In nail work, this concept shows up when a liquid monomer reacts with powder to form a durable acrylic film—the monomer molecules join the powder units to grow a hard coating.

Why this fits best: the defining feature of a monomer is its ability to bond and link into long chains, which is exactly what the option describes. The other ideas don’t fit: something that cannot bond isn’t a monomer, a large piece of polymer is what you get after many monomers have linked, and a solvent is a substance used to dissolve other materials rather than a monomer capable of forming polymer chains.