Concept:Lactose is a disaccharide, meaning it is made of two simple sugar units joined together.Explanation:Lactose is formed by one molecule of glucose and one molecule of galactose. They are linked by a β-1,4-glycosidic bond. This sugar is naturally found in milk and dairy products, which is why it is also called milk sugar. In the human body, the enzyme lactase breaks lactose into its two simpler sugars, glucose and galactose, for absorption. People who lack enough lactase suffer from lactose intolerance and cannot digest lactose properly. Other common disaccharides include sucrose (glucose + fructose) and maltose (glucose + glucose). Lactose also helps the body absorb calcium, which is important for bone health, especially in infants.Answer:Glucose and Galactose (Option D)