Which of the following is an example of a monomer used in building carbohydrates?

The correct answer is sugars, as they are the fundamental building blocks known as monosaccharides, which link together to form larger carbohydrate molecules like disaccharides and polysaccharides. Monosaccharides such as glucose, fructose, and galactose are essential components in energy metabolism and serve as the primary energy source for cells. When these monosaccharides join through glycosidic bonds, they create more complex carbohydrates, allowing for a variety of structures and functions, including storage forms like starch and glycogen, as well as structural components like cellulose.

In contrast, amino acids are the building blocks of proteins, not carbohydrates; nucleotides are the components of nucleic acids like DNA and RNA; and fatty acids are the basic units that form lipids, such as triglycerides and phospholipids. Understanding these distinctions is key to recognizing how different biomolecules function and are synthesized in biological systems.