Understand that proteins are large, complex molecules that play many critical roles in the body. They are made up of smaller units called monomers.
Identify the four options given: Amino acids, Fatty acids, Nucleotides, and Monosaccharides.
Recall that amino acids are the building blocks of proteins. They link together in chains to form proteins.
Recognize that fatty acids are components of lipids, nucleotides are the building blocks of nucleic acids, and monosaccharides are the building blocks of carbohydrates.
Conclude that the correct monomer for proteins is amino acids, as they are the specific building blocks that form protein structures.