Charles and Francis Darwin Concluded from Their Experiments on Phototropism

Multiple Choice

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the ________.

A) tip of the coleoptile
B) elongating cells in the coleoptile
C) base of the coleoptile
D) cotyledon
E) phytochrome in the coleoptile