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Complete Question Explanation

Flaw in the Reasoning. The correct answer choice is (D)

Unlike in the last question, this stimulus contains an argument, flawed though it may be. The science writer considers two theories, both of which reach the same prediction that galaxies accelerate away from one another. The first theory, posited by Lemaitre, is that of the “primeval atom,” which says that the universe emerged from the explosion of “a singular point of infinite gravity in space and time.” The second theory, not described in detail, is the “oscillating universe” theory. Both theories correctly predict that galaxies accelerate away from each other, a fact confirmed by observation.

However, the science writer concludes that Lemaitre’s theory “must be considered inadequate.” The sole reason for this conclusion is that the oscillating universe theory makes the same prediction regarding galaxies accelerating away from one another. This conclusion is flawed, and is based on a number of assumptions. One assumption is that Lemaitre’s theory does not incorporate the substance of the oscillating universe theory. Another assumption is either theory, let alone Lemaitre’s, must be considered incomplete if another theory makes the same prediction.

This is a Flaw in the reasoning question. Our prephrase is that the science writer errs by concluding that the mere fact that another theory makes the same, accurate prediction means that Lemaitre’s theory must be considered incomplete.

Answer choice (A): This answer choice is inconsistent with the writer’s argument, which did not rely on the credibility of either expert. Instead, the writer focused on the accuracy of the predictions made by both theories.

Answer choice (B): Here, the answer choice refers to the unambiguous use of a key term. However, the argument did not contain any such ambiguity. The repeated key terms, i.e., theory and observation, are used consistently throughout the argument.

Answer choice (C): The stimulus discussed only one observed phenomenon, that galaxies accelerate away from one another, so this answer choice does not accurately describe what occurred in the stimulus.

Answer choice (D): This is the correct answer choice because it correctly describes the science writer’s error in thinking that because the oscillating universe theory also predicts that galaxies accelerate away from one another, then Lemaitre’s theory must be considered inadequate.

Answer choice (E): The writer does not presume that there are only two possible explanations for the fact that galaxies accelerate away from one another. Rather, the writer appears to assume that if two theories make the same, accurate prediction, then at least one of the theories must be incomplete.

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