Reading comp PrepTest 132 · Section 1 · Question 4

Passage

Questions 1-8  .        To study centuries-old earthquakes and the geologic  . faults that caused them, seismologists usually dig  . Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Traditional approach to dating earthquakes (radiocarbon dating of carbon 14 isotopes in organic material near faults)
  • Views, minor Meta-Structures, and the author's attitude
    • Old approach:
      • Radiocarbon dating (of carbon 14 isotopes) of organic material trapped in sediments that show evidence of having shifted near fault lines (first through third sentence)
      • This can show the location and frequency of past earthquakes and the likelihood of future earthquakes (last sentence)

Paragraph 2

  • Paragraph note
    • New approach to dating earthquakes (lichenometry — measuring lichen growth along rocks)
  • Views, minor Meta-Structures, and the author's attitude
    • New approach:
      • Bull and Brandon developed lichenometry, which involves measuring lichen growth along rocks exposed by rockfalls following earthquakes (first through fourth sentences)
      • The number of rockfalls can show how strong the earthquake was and the location of rockfalls can help map the earthquake's epicenter (seventh and last sentences)
    • Example of lichen's slow and steady growth:
      • North American lichen, which grows 9.5 mm/year (fifth sentence)
    • Author's attitude: "provides direct evidence" (sixth sentence); "would imply" (seventh sentence); "can then be determined" (last sentence)

Paragraph 3

  • Paragraph note
    • Author on disadvantages of radiocarbon dating (not accurate in last 300 years, as the environment affects isotopes) and Bull/Brandon's requirements for lichenometry (minimize/factor disturbances like snow, shade, wind)
  • Views, minor Meta-Structures, and the author's attitude
    • Author's view:
      • Lichenometry has distinct advantages over radiocarbon dating, the latter of which is only accurate to within +/- 40 years and not of much use in the past 300 years (first through third sentences)
    • Bull and Brandon's view:
      • Lichenometry is accurate to within +/- 10 years and best in the past 500 years, but one needs to take into account the factors that can speed or slow lichen growth, like snow, wind, and shade (fifth through last sentences)
    • Cause-and-effect relationships:
      • Radiation on the Earth's upper atmosphere causes the amount of carbon 14 isotope to vary (second sentence)
      • Heavy radiation fluctuation in the last 300 years causes radiocarbon dating during this era to be useless (third sentence)
      • Snow avalanches and other disturbances can cause lichen growth to slow down (last sentence)
      • Shade and wind causes lichen growth to speed up (last sentence)
    • Author's attitude: "distinct advantages" (first sentence); "accurate only to within plus or minus 40 years" (second sentence); "fluctuated greatly" (third sentence); "of little value" (third sentence)

Main Point: Even though it requires careful site selection and calibration, lichenometry, a new technique for dating past earthquakes, has several advantages over the traditional radiocarbon dating technique.

Meta-Structure?

OldApproach/New Approach: This passage fits the Old Approach/New Approach Meta-Structure like a glove. In such a passage, the author will typically start by describing an old way of doing something or thinking about something. Often, this is referred to as the "traditional" approach or theory). The author will then describe a new, alternative way of doing or thinking about that same thing. Usually, the author prefers the new approach.

That's what happens here. The author introduces the "usual[]" technique in the first paragraph before shifting to the new technique in the second. When a passage utilizes this Old Approach/New Approach Meta-Structure, the author's opinion on the new approach is usually the main point. Here, the author feels that it has "distinct advantages" over the old technique, so we should ground our understanding of the main point in that view.

Last Thoughts?

Be careful with the end of this passage, starting in the fifth sentence of the last paragraph (beginning with "They note"). The author pivots here, stating that Bull and Brandon note some limitations on lichenometry — careful site selection and calibration. However, that doesn't undercut the author's claim that lichenometry has "distinct advantages" over radiocarbon dating, so we shouldn't feel as if this section is enough to make the author want to abandon the practice. That opening line of the third paragraph is still the clearest statement of the author's opinion.

Question prompt

Which one of the Remaining source text redacted.
Why the credited answer is right

Credited answer: B

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

Question Type

Science

Strategy Overview

Remind ourselves of the main point of the passage, then head to the answers, focusing on those that line up with the main point and then using our notes/the passage to find the correct answer

Answer Anticipation

This question asks us to infer, based on the entire passage, a statement that must be true. Such questions can be very challenging. These questions provide little indication as to the topic of the correct answer or where it’ll show up in the passage. Moreover, the correct answer probably won't restate something from the passage. Instead, the question will likely require us to draw a connection between a few different pieces of information.We’ll need to rely on our big-picture understanding of the passage to answer these questions. We should start by reminding ourselves of the main point (either by reviewing what we said after reading the passage or by rereading our answer to the main point question). From there, we can head to the answer choices. If something in an answer choice doesn't seem familiar and isn’t reflected in our notes on each paragraph, we shouldn’t check the passage to see if it was mentioned. Instead, we’ll table it and move on to the next answer choice. If something seems inconsistent with the main point, we can eliminate it. If something seems familiar, consistent with the main point, or reflected in our notes, we’ll use our notes/highlights/underlines to find the part of the passage that proves the answer choice must be true. If we can find that confirmation, we’ll select that answer choice and move on.

Answer choices

  1. A
    Lichenometry is less accurate Remaining source text redacted.
    Why choice A is not credited

    (A) Is this consistent with the main point or reflected in our notes?

    Nope. The main point highlights the advantages of lichenometry over radiocarbon dating, so this answer choice cuts against the main point. For this reason, we can eliminate (A) without checking the passage.

    Besides, we wouldn't find support for this answer choice even if we reviewed the passage. This answer is about limitations on lichenometry, so it would show up in the third paragraph. However, that paragraph is mostly about the advantages of lichenometry over radiocarbon dating, and even the limitations on lichenometry aren't framed as things that radiocarbon dating does better. While the passage does note that radiocarbon dating can "provide hints about the likelihood and location of future earthquakes" (P1, S4) and it's silent as to the ability of lichenometry to do the same, that doesn't mean the former is better at it than the latter. If we say that Wendy's has good fries and we don't mention McDonald's fries, that doesn't mean we think the former are better than the latter!

  2. B
    Radiocarbon dating is unlikely Remaining source text redacted.
    Why choice B matches the stem

    (B) Is this consistent with the main point or reflected in our notes?

    Yes. Our note for the first paragraph says, "Traditional approach to dating earthquakes (radiocarbon dating of carbon 14 isotopes in organic material near faults)." Since this technique is performed "near faults," it's possible that we can't use the technique if there are "no identifiable fault lines associated" with the earthquake. Therefore, it's worth checking the passage to confirm that this must be true.

    Since this answer choice deals with the process of radiocarbon dating, we should check the first paragraph. There, we see that the process involves "dig[ging] trenches along visible fault lines" and dating the organic materials in the sediment trapped there (P1, S1). As such, if there are no visible fault lines, there's no place to dig and no sediment to date. So, this answer is correct. We can justifiably select it and advance straight to the next question.

  3. C
    Radiocarbon dating and lichenometry Remaining source text redacted.
    Why choice C is not credited

    (C) Is this consistent with the main point or reflected in our notes?

    Nope. Neither the main point nor our notes reference whether radiocarbon dating and lichenometry are the only methods to detect and date past earthquakes. Plus, this answer choice uses the bold, SCOOTS-y language ("only") that's unlikely to appear in the correct answer to a Must Be True question. For these reasons, we can eliminate — or at least table — (C) without checking the passage.

    Besides, we wouldn't find support for this answer choice even if we reviewed the passage. At no point does the passage discuss any other methods or whether these are the only two methods. As such, we can feel comfortable eliminating this answer choice.

  4. D
    Radiocarbon dating is more Remaining source text redacted.
    Why choice D is not credited

    (D) Is this consistent with the main point or reflected in our notes?

    No. The main point emphasizes the advantages of lichenometry over radiocarbon dating, so this answer choice is inconsistent with the main point. For this reason, we can eliminate (D) without checking the passage.

    Besides, we wouldn't find support for this answer choice even if we reviewed the passage. This answer is about the relative advantages of the methods, so we would check the third paragraph. There, we'd see that radiocarbon dating is "of little value" during the past 300 years (P3, S3), and lichenometry is "best used" for earthquakes within the past 500 years (P3, S5). So, while radiocarbon dating might be of some value, 400 years is within the lichenometry sweet spot. If anything, it seems that it would be better here than the alternative.

  5. E
    The usefulness of lichenometry Remaining source text redacted.
    Why choice E is not credited

    (E) Is this consistent with the main point or reflected in our notes?

    Negative. Our note for the third paragraph reads, in part, "Bull/Brandon's requirements for lichenometry (minimize/factor disturbances like snow, shade, wind)." Since we can factor in "disturbances like snow, shade, [and] wind," it doesn't seem like lichenometry is "limited" to places where these disturbances aren't present. Therefore, our notes contradict (E), allowing us to eliminate it without checking the passage.

    Besides, we wouldn't find support for this answer choice even if we reviewed the passage. This answer is about a limitation of lichenometry, so we should check the end of the third paragraph. There, we can see that the passage says sites must be selected carefully and that disturbances that accelerate or impede growth "must be factored in" (P3, S5-S6), but at no point does it say that such disturbances prevent the accurate use of lichenometry, as this answer suggests ("limited to").

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 4%
  2. B Credited 30%
  3. C 4%
  4. D 2%
  5. E 61%

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