Which of the following is a polysaccharide?

Starch is classified as a polysaccharide because it is a complex carbohydrate made up of long chains of glucose molecules. Unlike simple sugars (monosaccharides like galactose) or disaccharides (such as sucrose, which consists of glucose and fructose, and maltose, which consists of two glucose molecules), starch consists of many glucose units linked together. This structure allows starch to serve as a significant energy storage form in plants.

Polysaccharides, including starch, are important for providing energy and sustaining long-duration activities because they can be broken down slowly into glucose, supplying a steady source of energy. In contrast, the other options are single or double sugar units that do not possess the long-chain structure characteristic of polysaccharides.