## **Core Concept**
Human breast milk has a unique composition tailored to the nutritional needs of infants. It contains various nutrients, antibodies, and immunoglobulins essential for infant growth and immune system development. The comparison with cow's milk highlights these differences.

## **Why the Correct Answer is Right**
Human breast milk is notably rich in **lactose** when compared to cow's milk. Lactose serves as a crucial energy source for infants, supporting their rapid growth and brain development. This higher lactose content is a key characteristic that distinguishes breast milk from cow's milk.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While breast milk does contain proteins, the statement is too vague as it doesn't specify the type or amount. Both breast milk and cow's milk contain proteins, but their types and quantities differ.
- **Option B:** This option is incorrect because while breast milk does contain antibodies (immunoglobulins), the question seems to focus on nutritional components like carbohydrates, proteins, and fats.
- **Option C:** This option is incorrect because cow's milk actually contains a higher amount of **casein** (a type of protein) compared to breast milk. Breast milk has a higher proportion of **whey proteins**, which are easier for infants to digest.
- **Option D:** This option might seem plausible because breast milk and cow's milk both contain fats, but the question emphasizes what breast milk is particularly rich in compared to cow's milk, which points more towards lactose.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that breast milk contains a higher lactose and lower casein content compared to cow's milk. This is why **lactose intolerance** is rarely an issue in infants, and why cow's milk formulas often need to be adjusted to more closely match human milk.

## **Correct Answer:** . Lactose