A disaccharide is formed by the joining of how many monosaccharides?

A disaccharide is formed specifically by the joining of two monosaccharides through a glycosidic bond. This process, known as dehydration synthesis or condensation reaction, involves the removal of a water molecule as the two monosaccharides link together. Common examples of disaccharides include sucrose, which is composed of glucose and fructose, and lactose, which is made up of glucose and galactose. The fundamental characteristic of disaccharides is that they consist of precisely two monosaccharides; therefore, the correct answer highlights this essential relationship in carbohydrate chemistry. Monosaccharides are the simplest form of carbohydrates, and when two of these units come together, they create a disaccharide, marking a crucial step in the complexity of carbohydrate structures.