Reading comp PrepTest 150 · Section 1 · Question 4

Passage

Questions 1-5  . The following passage was written in the mid-1990s.  .             Evidence that the earth's atmosphere has warmed  . Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Phenomenon: Earth's annual temperature increase; evidence links the increase to the greenhouse effect
  • Views, minor Meta-Structures, and the author's attitude
    • Comparison:
      • The current average temperature is about 0.5 degrees Celsius higher than it was 100 years ago (second sentence)
    • Cause-and-effect relationship, according to proponents of the greenhouse effect:
      • Elevated levels of certain gases cause heat to be trapped in the earth's atmosphere (last sentence)
    • Author's attitude: "quite compelling" (first sentence); "unprecedented" (second sentence); "strengthened" (last sentence); "controversial" (last sentence)

Paragraph 2

  • Paragraph note
    • Inconsistencies in greenhouse effect data and correction with updated data taking sulfates into account
  • Views, minor Meta-Structures, and the author's attitude
    • Comparison, according to early models of the greenhouse effect:
      • Models estimate that increase in the earth's atmosphere should have been higher than the observed increase (first sentence)
      • Taking into account sulfates causes data to be consistent with observed temperatures (last sentence)
    • Cause-and-effect relationship:
      • Airborne sulfates cause solar energy to reflect back to space, which causes a lowering of the temperature (third sentence)
    • Example of sources of sulfates:
      • Natural sources, like volcanoes (third sentence)
      • Human technological sources (third sentence)
    • Author's attitude: "somewhat inconsistent" (first sentence); "more accurately" (second sentence); "important factor" (second sentence)

Paragraph 3

  • Paragraph note
    • Alternative explanation (solar energy) and rebuttal (can't explain long-term and extreme fluctuations); author's conclusion
  • Views, minor Meta-Structures, and the author's attitude
    • Solar energy view:
      • The sun's heating effects have changed the earth's atmospheric temperature (first and second sentences)
    • Author's view:
      • Solar energy models can explain yearly fluctuations but not the long-term, extreme increases in average temperature (third through fifth sentences)
      • The earth's annual temperature has increased, and the greenhouse effect is the best explanation for that increase (last sentence)
    • Author's attitude: "strong" (second sentence); "cannot account for the entirety" (third sentence); "it seems reasonable to conclude" (last sentence)

Main Point: New methods in data collection and analysis establish the greenhouse effect as the most likely cause of the rise in annual global temperatures.

Key Lines?

Paragraph 1, Sentence 1 (P1, S1) - Description of phenomenon (rise in temperatures)

P1, S3 - Explanation of phenomenon (greenhouse effect)

P2, S1 - Issue with explanation (inconsistencies in early models)

P2, S2-4 - Correction of the issue (airborne sulfates account for inconsistencies)

P3, S1 - Alternative explanation (changes are due to variations in solar energy)

P3, S3 - Rebuttal of the alternative explanation (can't account for the entirety)

P3, S6 - Author's conclusion

Meta-Structure?

Phenomenon/Explanation: This passage follows the Phenomenon/Explanation Meta-Structure. When passages utilize this Meta-Structure, the initial paragraphs typically describe an observable fact, behavior, or situation. We call these "phenomena." The author then describes one or more "explanations" of why the observable fact, behavior, or situation occurs in later paragraphs.

This passage follows that model closely. In the first two sentences of the first paragraph, the author describes and supports the phenomenon — Earth's increasing annual temperatures — through references to data. In the last sentence of that paragraph, the author introduces a "controversial" explanation for the increase: the greenhouse gas effect. The author describes and accounts for some issues with this explanation in the second paragraph and rebuts an alternative explanation in the third paragraph*. Ultimately, the author concludes that the greenhouse effect is the best explanation for the phenomenon in the last sentence. Since the main point is generally the explanation the author presents or endorses in a Phenomenon/Explanation passage, we can use that sentence to help us answer the main point question.

*Because the author uses the second and third paragraphs to rebut criticisms or issues with the greenhouse effect explanation, some may view this as a Rebutting Critics or Criticizing a Viewpoint passage. However, these rebuttals support the author's preferred explanation, so we felt the Phenomenon/Explanation Meta-Structure fit this entire passage's structure better.

Last Thoughts?

Passages tend to be a bit dated in Reading Comprehension. So, if you felt it was odd that the passage referred to the link between atmospheric gases and temperature increases as "controversial" within the scientific community, that's your explanation. (Helpfully, the caption above the passage clarifies how old this passage is.) Let this remind us that we shouldn't bring our prior knowledge or assumptions about a topic into our reading method. While we may rely on some well-known or common-sense beliefs and suppositions in Reading Comprehension (for instance, it would be difficult to understand this passage without knowing that there's an atmosphere surrounding the earth), almost everything we'll need to answer the questions is written in the passage. We need to read and understand the actual text of the passage — we shouldn't rely on any specific or specialized extra-textual knowledge or beliefs about the subject matter on Reading Comprehension.

Question prompt

It can be reasonably Remaining source text redacted.
Why the credited answer is right

Credited answer: E

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Science

Strategy Overview

Consult your notes or passage to recall the author's attitude about the topic in question, and find the answer that best reflects your understanding of the author's opinion on that topic

Answer Anticipation

This question asks us to find the answer choice that the author would argue presents the most crucial factor to consider when judging explanations of the global temperature trends over the last 100 years. Reviewing our notes, we'll notice the author evaluates both the solar energy and greenhouse gas explanations of the rising temperatures in the third paragraph. In that paragraph, the author discounts the solar energy explanation because it can explain only yearly fluctuations in temperature but not the long-term, extreme increases in average temperature (P3, S3-5). According to the author, the current rise in global temperatures "surpasses the most extreme fluctuations in temperature consistent with the models based on variations in solar energy" (P3, S5).Notably, the author prefers the greenhouse gas explanation (P3, S6). Earlier, the author said that models based on this explanation (taking into account airborne sulfates) have allowed scientists to develop "calculated theoretical temperatures for recent decades that are consistent with observed temperatures" (P2, S4). So, in both the second and third paragraphs, the author appeals to models and temperature data to corroborate the greenhouse theory. The author dismisses the solar energy theory because the models do not match the long-term observed temperature data. The author endorses the greenhouse gas explanation because its models provide such a match. Therefore, the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations.

Answer choices

  1. A
    a strong correspondence between Remaining source text redacted.
    Why choice A is not credited

    (A) Does this say the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations?

    Well, this answer choice mentions correspondence between a model's data and the observed temperature data, so it warrants a closer inspection. Upon a closer look, we'll notice that it's missing the "long-term" part. In dismissing the solar energy theory, the author acknowledges that models based on that theory can show a "strong decade-by-decade correspondence" between solar energy and temperatures (P3, S2). Even though the models based on this theory establish a strong correspondence over a few years, the author ultimately rejects the theory because its models project long-term temperature stability and thus cannot explain the dramatic temperature increase (P3, S3-5). Clearly, the "long-term" correspondence is crucial to the author, making (A) incorrect.

  2. B
    that the model predicts Remaining source text redacted.
    Why choice B is not credited

    (B) Does this say the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations?

    Nope. This doesn't discuss data at all. Instead, it focuses on predicting an increase in temperature. Although the author thinks the model should account for the recent temperature increase, the author also wants the model to match the long-term, real-world temperature data. Moreover, the author wants to compare the model to past temperatures, not predict future temperatures.

  3. C
    the extent to which Remaining source text redacted.
    Why choice C is not credited

    (C) Does this say the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations?

    No. Although the author approved of the greenhouse gas theory once its models were revised, that's not why the author supported this theory. Instead, the author defended the greenhouse gas theory by citing its models' ability to match real-world temperature data over a long period.

  4. D
    a close fit between Remaining source text redacted.
    Why choice D is not credited

    (D) Does this say the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations?

    Nope. Besides, the author never defends the greenhouse gas theory because its warming mechanism is "generally acknowledged" to raise atmospheric temperatures. In fact, the author calls the greenhouse effect "controversial" and still defends it (P1, S2). So, whether the theory is generally accepted is not crucial to this author.

  5. E
    a long-term match between Remaining source text redacted.
    Why choice E matches the stem

    (E) Does this say the author would want an explanation to produce temperature estimates that match the long-term, real-world temperature observations?

    Finally, yes. This matches our anticipation nicely. Plus, unlike (A), answer choice (E) describes a "long-term match" — a sticking point for this author. Therefore, we can select (E) with confidence.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 27%
  2. B 3%
  3. C 9%
  4. D 7%
  5. E Credited 55%

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