Which developmental principle is demonstrated by the infant motor milestones of lifting one's head, pivoting the upper body, sitting, and finally standing?

cephalocaudal sequence

Explanation:

The cephalocaudal theory refers to the general pattern where the greatest growth occurs at the top of the body, i.e. the head, and gradually the physical development shifts downward: e.g. back, arms, spine, etc. It is a general pattern of physical and motor development with a continuum from infancy to puberty and follows a development pattern from head-to-toe.

d. the polar jet stream   lies between the polar easterlies and trade winds should be your answer