Which of the following is NOT a monosaccharide?

Starch is not a monosaccharide; rather, it is a polysaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of single sugar molecules that cannot be hydrolyzed into simpler sugars. Examples include fructose, glucose, and ribose, all of which have singular structures and specific functions in biological systems.

Starch, on the other hand, is composed of many glucose units linked together in a chain, forming a complex carbohydrate that serves as an energy storage molecule in plants. This distinction between simple sugars (monosaccharides) and complex sugars (polysaccharides like starch) is fundamental in understanding carbohydrate classification and their respective biological roles.