Final answer:
The Moro reflex, an instinctive response in infants to the sense of falling, involves spreading out the arms, pulling them back in, and usually crying. It is designed to help the infant grasp the caregiver in a fall-like situation.
Step-by-step explanation:
The Moro reflex occurs in response to the sense of falling. This reflex is an instinctive behavior in infants that serves as a protective mechanism. When infants experience a sudden loss of support, they instinctively react with a sequence of movements: they spread out their arms, then pull them back in, and usually cry out. This is an automatic response that appears to help an infant potentially reach out and grasp their caregiver, which would aid in preventing an actual fall and maintaining close contact.
Another related reflex in infants is the grasping reflex, where an infant instinctively grasps a finger or object placed in their palm, also thought to aid in maintaining physical contact with the caregiver. This reflex is present even before birth and persists until about five to six months of age.