Final answer:
Infants' states of alertness become more regular over the first two months after birth.
Step-by-step explanation:
During the first two months after birth, infants' states of alertness become more regular. Newborns spend most of their time sleeping, crying, and eating, but as they develop, their sleep patterns become more regulated and they spend more time awake. By the end of their first year, infants are typically awake as much as they are asleep, indicating a significant change in their regularity of states of alertness.