(4) Lactose Explanation: The main sugar found in milk is known as lactose, which is a natural sugar that is made up of glucose and galactose. It provides a mildly sweet taste to milk. It makes up around 2- 8% of the solids in milk. Lactase, found in the small intestine, breaks down lactose into two simpler forms of sugar: glucose and galactose, which is then absorbed by the body.