Final answer:
The enzyme that breaks down lactose, the sugar found in milk, is called lactase.
Step-by-step explanation:
The enzyme that breaks down the type of sugar found in milk is lactase. Lactase is responsible for hydrolyzing lactose, a disaccharide, into its component monosaccharides: glucose and galactose. This breakdown is essential for proper digestion and absorption of milk sugars in the small intestine. Individuals who produce insufficient amounts of lactase may experience lactose intolerance, which can lead to gastrointestinal discomfort when consuming milk and dairy products.