Final answer:
Lactose is the sugar found in higher concentrations in human milk compared to cow's milk, with approximately 7.5% in human milk versus 4.5% in cow's milk.
Step-by-step explanation:
In human milk, the sugar found in much higher concentrations compared to cow's milk is lactose. Human milk contains approximately 7.5% lactose, whereas cow's milk has about 4.5%. Lactose, which is less sweet than sucrose, consists of two monosaccharides, glucose and galactose. When lactose is hydrolyzed, it breaks down into these two components. Galactose is especially significant for babies as it contributes to the development of the brain and nerve cells. Moreover, lactose is important as an infant food and aids in the production of substances like penicillin.