Rennin's primary function is to curdle milk in the stomach of infants.

Rennin's primary function is to curdle milk in the stomach of infants.

• A. Activation of pepsin
• B. Digestion of fats
• C. Absorption of minerals
• D. Milk curdling

Answer: (D)

Rennin is a proteolytic enzyme in the infant stomach that acts on the milk protein casein to form a soft curd. This curdling slows the rate at which milk leaves the stomach and makes the proteins easier to digest, which is its defining role in infant digestion. It isn’t involved in activating pepsin, digesting fats, or absorbing minerals—those tasks are handled by other enzymes and processes. So the best description of its primary function is milk curdling.

Rennin is a proteolytic enzyme in the infant stomach that acts on the milk protein casein to form a soft curd. This curdling slows the rate at which milk leaves the stomach and makes the proteins easier to digest, which is its defining role in infant digestion. It isn’t involved in activating pepsin, digesting fats, or absorbing minerals—those tasks are handled by other enzymes and processes. So the best description of its primary function is milk curdling.