Final answer:
The behavior of Andrea's newborn in holding a rattle is due to the palmar grasp reflex, an innate response that supports close physical contact with caregivers and survival in infants.
Step-by-step explanation:
Andrea's newborn's ability to hold a rattle when it is placed in her hand is due to a natural and innate response known as the palmar grasp reflex. This reflex is observed when a baby automatically grasps anything that comes into contact with their palms. The grasp reflex is strong and it is present from birth, generally lasting until the infant is about five to six months old. This reflex helps the baby in maintaining close contact with the caregiver, which is crucial for the baby's survival during the early stages of life.
Other reflexes that are present in newborns include the Moro reflex, which is a response to the sensation of falling, and the sucking reflex, which helps the infant feed. These reflex behaviors support the infant's survival as they facilitate feeding and the ability to stay safely in close proximity to a caregiver.