Critical Reasoning - Author's Reasoning

GMAT® Verbal Practice Question

This GMAT verbal practice question is a critical reasoning question. The task at hand is to identify the reasoning provided by the author of the argument.


Industrial and automobile pollution have long been thought to contribute to global warming. However, researchers have identified that the carbon dioxide and carbon monoxide released into the atmosphere are not as potent as the methane emitted by cud-chewing animals such as cows when they fart or belch. Therefore, if you drive a hybrid electric car to the grocery, any favor that you would do to the environment would be offset if you end up buying beef.

Which of the following best describes the author's reasoning?

  1. The author establishes a point by drawing an analogy
  2. The author disproves a popular notion by providing evidence that is contrary to it
  3. The author presents a new theory in response to an existing well-established theory
  4. The author uses an illustration to support a new school of thought that is contrary to a popular school of thought
  5. The author makes a comparison between two theories by providing an example

Explanatory Answer

Video explanation will be added soon.
  1. Step 1: Analyzing the Argument

    The argument discusses the various factors that cause global warming. The author refutes the popular belief that industrial and automobile pollution are the primary factors and presents an alternative theory that cattle belching has a greater impact. Although not explicitly stated, the author implies that cattle farming is a contributor by stating that beef consumption contributes to global warming. The correct answer must capture this reasoning used by the author.

  2. Step 2: Eliminating Options

    • An analogy is a comparison. For the author to draw an analogy, he should be saying that what happened in the case of X is true again in the case of Y. However, the author does not make any such comparison and option (A) can be eliminated.
    • The author has presented a counter theory made by some researchers. The author has also presented a hypothetical scenario explaining the counter theory. However, at no point has the author provided any “evidence”. An evidence has to be some kind of data or irrefutable fact used by the author. Since the argument presents no evidence, option (B) can be eliminated.
    • While the author does present a theory that is contrary to another, the theory presented is not the author’s own but that of the researchers. The option that correctly describes the author’s reasoning must take into account the last statement of the argument, which is the primary statement that presents the author’s perspective. However, option (C) fails to capture this.
    • The example provided by the author is not done with the objective of comparing two theories but with the objective of justifying one. Option (E) can be eliminated.
    • The author is providing an illustration of the new theory in an effort to counter the long-established one. Choice (D) is an apt description of the argument.
Option D is the correct answer.

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