After Some Time, the Tip of a Plant That Has

Multiple Choice

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) accumulation of amyloplasts on the lower side of the stem
C) gibberellin production by stems
D) exposure of phytochrome in the stem to red light
E) auxin movement toward the lower side of the stem