Answer:
Plants stem grow against the gravity while roots grow towards the gravity and this prices is known as the geotropism or gravitism explains that the roots grow toward the direction of the gravity pull termed as positive geotropism.
Auxin is a hormone that acts at the bottom of the cell and have different function in roots and stems as in stems it promotes the elongation of the cell against gravity while in roots it is promotes the elongation of the cell towards the gravity.
