Question

if in a root region of meristematic activity cells divide repeatedly then why region of elongation are considered responsible for growth of root ?

Answer 1

Root growth occurs by division of stem cells in the root meristem located in the tip of the root, and the subsequent expansion of cells in a region just proximal to the tip, the elongation zone. Cell elongation is closely related to root development processes. Root tip responses to gravity and then be relayed to the elongation zone so as to maintain growth direction. That is why elongation zone considered responsible for growth.