Question

why is the growth of root is due to gravitropic movement

Answer 1

FOR WATER AND MINERAL UPTAKE,,,,,,,,,,,,,,,

Answer 2

Root growth occurs by the 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 primal to the tip known as the elongation zone. Differential growth during tropisms mainly involves changes in cell expansion versus changes in cell division, although a role for cell division in tropic growth has not been formally ruled out. Gravity is sensed in the root tip and this information must then be relayed to the elongation zone so as to maintain growth direction and mount effective growth responses to changes in orientation to and continue to grow its roots in the same direction as gravity.[