What is an example of a disaccharide?

Lactose is classified as a disaccharide because it consists of two monosaccharide units: glucose and galactose. Disaccharides are carbohydrates formed when two monosaccharides undergo a condensation reaction, resulting in the formation of a glycosidic bond. Lactose is the sugar found in milk and is a key source of energy, particularly in the diets of infants and young mammals.

Fructose and glucose, on the other hand, are monosaccharides, meaning they are single-sugar units and do not consist of two bonded monosaccharides. Starch, while a carbohydrate, is a polysaccharide composed of multiple glucose units bonded together, making it more complex than a disaccharide. Therefore, among the options presented, lactose is the only one that fits the definition of a disaccharide, highlighting its role as an important carbohydrate in nutrition.