Several scientists, including Charles and Francis Darwin, Frits Went and others, demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments. Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?
A. Auxin concentration was equal on both sides (lighted and shaded) of the stem; however, the apical meristem responded to the presence of light.
B. The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light.
C. Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem, and thus a bending in the direction of the light.
D. A combination of positive phototropism and a negative gravitropism.
E. The stems actually were responding to the agar blocks that had been used in the experiments.
Answer: B
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