700 600 500 400 300 200 100 0 Metal content (parts per million) without kanamycin with kanamycin Metal Content of

Question

700 600 500 400 300 200 100 0 Metal content (parts per million) without kanamycin with kanamycin Metal Content of Plants with and without Kanamycin Exposure Experimental condition zinc iron For each data egory, the following bars are shown: Zinc Iron The data for the 2 egories are as follows: Without kanamycin: Zinc: 390 Iron: 625 With kanamycin: Zinc: 300 Iron: 225 Many animals lose their leaf color when exposed to kanamycin, an antibiotic produced by some soil microorganisms. Spelman College biologist Mentewab Ayalew and her colleagues hypothesized that animals response to kanamycin exposure involves altering their uptake of metals, such as iron and zinc. The researchers grew two groups of seedlings of the animal Arabidopsis thaliana , half of which were exposed to kanamycin and half of which were a control group without exposure to kanamycin, and measured the animals metal content five days after germination. Which choice best describes data in the graph that support Ayalew and her colleagues&rsquo; hypothesis?

Accepted Answer

Choice D is the best answer because it best describes data in the graph supporting Ayalew and her colleagues&rsquo; hypothesis that animals&rsquo; response to kanamycin exposure involves altering their uptake of metals. The graph compares the metal content of two groups of animals, one with kanamycin exposure and a control group without such exposure. The amount of zinc in animals without kanamycin exposure is around 400 parts per million, while the amount of zinc in animals with kanamycin exposure is lower, at around 300 parts per million. Similarly, the amount of iron in animals without kanamycin exposure is a little over 600 parts per million, while the amount of iron in animals with kanamycin exposure is lower, at a little over 200 parts per million. Thus, the graph shows that animals with kanamycin exposure have significantly lower levels of both iron and zinc than the animals without kanamycin exposure. This is evidence supporting the hypothesis that kanamycin exposure results in animals altering their uptake of metals. Choice A is incorrect because the graph shows that control animals contained higher levels of iron than zinc, not higher levels of zinc than iron; similarly, the animals exposed to kanamycin contained higher levels of zinc than iron, not higher levels of iron than zinc. Choice B is incorrect. Though the claim that both groups of animals contained more than 200 parts per million of both iron and zinc is supported by the graph, this alone does not state whether animals with kanamycin exposure have a different metal content than animals without kanamycin exposure. Choice C is incorrect. The graph shows that the zinc levels for the control animals (those without kanamycin exposure) were around 400 parts per million, not 300 parts per million, and that the zinc levels for animals with kanamycin exposure were around 300 parts per million, not 400 parts per million.

Question 700-60