After some time, the tip of a plant that has been forced into a horizontal position grows upward. This phenomenon is related to
A) calcium release from the endoplasmic reticulum of shaded cells.
B) whether the plant is in the northern or southern hemisphere.
C) gibberellin production by stems.
D) auxin production in cells receiving red light.
E) auxin movement toward the lower side of the stem.

Question

Quizplus · Accepted Answer

This phenomenon is known as gravitropism and is related to the movement of the plant hormone auxin toward the lower side of the stem. When the plant is forced into a horizontal position, auxin accumulates on the lower side and promotes cell elongation, causing the tip to curve upward.

After Some Time, the Tip of a Plant That Has