In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order :-

The extreme tip of the root is covered by a thimble-like root cap, which protects the tender apex as it pushes through the soil.
Just behind (above) the root cap is the region of meristematic activity, where small, thin-walled cells divide repeatedly (cell division).
Above this is the region of elongation, where the new cells enlarge and lengthen, pushing the root tip forward (cell enlargement).
Above this is the region of maturation, where cells differentiate into permanent tissues; root hairs arise from the epidermis here.
So from the tip upward the order is: root cap, cell division, cell enlargement, cell maturation.