Final answer:
Infants first develop the ability to hold their head up, followed by rolling from front to back, rolling from back to front, and finally the pincer grasp.
Step-by-step explanation:
Infants typically develop the ability to hold their head up first, usually within the first two months after birth. This is an important milestone in their motor development as it demonstrates increased head control and strength. Rolling from front to back usually occurs around the four-month mark, followed by rolling from back to front. The pincer grasp, where infants use the tips of their thumb and forefinger to pick up objects, typically develops around ten months of age.