Final answer:
Newborn Juliette is demonstrating the rooting reflex, which helps infants locate and suckle a nipple for feeding, crucial for their survival.
Step-by-step explanation:
When newborn Juliette turns towards her grandmother and opens her mouth in response to her cheek being touched, she is demonstrating the rooting reflex.
This reflex is an automatic behavior that helps infants locate a source of food, such as a mother's nipple, and begin to suck. The rooting reflex, along with other newborn reflexes such as the grasping reflex and the Moro reflex, are essential for a baby's survival as they help newborns feed and maintain close physical contact with their caregivers.