What are the states of a newborn characterized by alert activity, waking activity, crying, and sleeping?

The correct answer is "newborn states" because this term specifically refers to the various levels of alertness and activity patterns exhibited by a newborn. These states represent the functional and behavioral states that newborns cycle through, including alert activity, waking activity, crying, and different stages of sleep. Recognizing these states is essential for caregivers as it can help in understanding a newborn's needs and can guide interactions that support their development.

On the other hand, the other options do not accurately capture the concept described in the question. "Newborn stages" might suggest a progression or development over time rather than the immediate states of being. "Infant responses" could refer to how an infant reacts to stimuli but does not encompass the distinct categories of activity described. "Developmental milestones" pertains to specific skills or behaviors that infants typically achieve at certain ages, which is different from the immediate states of a newborn. Thus, "newborn states" is the term that best encompasses the specific behaviors and activity patterns of newborns.