本题目来源于试卷: Interaction & Interdependence C.6 Integration of Body Systems，类别为 IB生物学
[单选题]
Which sequence shows the route taken by aux8 6x 0n,hixdqwin from itse 3xixy f 0zu h4:7amd:g4km;h production to its role in phha 0:e4y h3iuxdm;f4:kx7 zmgototropism?
A. Step 1 is Produced in meristem ; Step 2 is Moves to shaded side ; Step 3 is Inhibits cell elongation
B. Step 1 is Produced on shady side ; Step 2 is Changes gene expression ; Step 3 is Promotes cell elongation
C. Step 1 is Produced on shady side ; Step 2 is Changes gene expression ; Step 3 is Inhibits cell elongation
D. Step 1 is Produced in meristem ; Step 2 is Moves to shaded side ; Step 3 is Promotes cell elongation
参考答案: D
本题详细解析:
Explanation: Choice D is correct because auxin is produced at the meristem in the stem tip and is moved to the shady side by efflux pumps, and the high concentrations on the shady side cause cell elongation. Choice A is incorrect because auxin does not inhibit cell elongation on the shady side. Choice B is incorrect because auxin is not produced on the shady side. Choice C is incorrect because auxin is produced at the meristem in the stem tip, not only on the shady side, and it does not inhibit cell elongation in stems.
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