Which of the following can indicate an infant's state of hunger?

The indication of an infant's state of hunger is best represented by vocal cries. Babies communicate their needs primarily through crying, and this vocalization can be a distinct signal that they are hungry. When an infant is hungry, they often exhibit different types of cries that can vary in pitch, volume, and duration.

While movement of the digestive system may occur, it is not a direct or reliable indicator of hunger in the way vocal cries are. Increased respiratory rate and changes in skin texture are not specific indicators of hunger; they can be related to other factors such as discomfort or environmental conditions. Therefore, vocal cries are the clearest and most recognized sign that an infant is signaling a need for food.