What are the building blocks of hair that link together to form tiny protein fibers?

The correct answer, amino acids, are indeed the fundamental building blocks of hair. Hair is primarily composed of a protein called keratin, which forms a structure through the linkage of numerous amino acids. These amino acids, through peptide bonds, connect in specific sequences to create long chains, which then fold into the complex structures that give hair its strength and resilience.

Proteins themselves are large molecules made up of one or more long chains of amino acids. While they are important in the structure of hair, they do not serve as the basic building blocks; rather, they are the end products formed from various combinations of amino acids.

Carbohydrates and fatty acids do not contribute directly to the formation of hair. Carbohydrates primarily serve as energy sources and play different roles in the body, while fatty acids are key components of lipids and play roles in cellular structures and energy storage. Therefore, amino acids are specifically crucial to hair structure, as they are the individual molecules that assemble into the proteins that make up hair fibers.