What Are the Subunits of Carbohydrates?

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Carbohydrates are separated into three subunits: monosaccharides, polysaccharides and oligosaccharides. Monosaccharides are the smallest of the subunits and are made up of single sugar molecules. The most common monosaccharides are the sugars fructose and glucose, and these typically take on a ring-shaped structure.