Final answer:
During breastfeeding, the stimulus of a baby sucking on the nipple increases milk production. This is an example of positive feedback and ensures the baby receives enough milk.
Step-by-step explanation:
During breastfeeding, the stimulus of the baby sucking on the nipple increases the amount of milk produced by the mother. This is an example of positive feedback because it enhances and amplifies the initial stimulus. The more the baby suckles, the more milk is produced. The evolutionary benefit of this milk production regulation mechanism is that it ensures that the baby receives enough milk to meet its growing nutritional needs.