Reading comp PrepTest 146 · Section 4 · Question 23

Passage

 .       By 1970 it was well established that ultraviolet  . light from the sun contributes to skin cancer.  . Fortunately, Remaining source text redacted.
Passage walkthrough
Passage SummaryTopic: Science

Paragraph 1
  • Paragraph note
    • A problem and something mitigating that problem are noted
  • Views, minor Meta-Structures, and the author's attitude
    • Problem - The sun (UV radiation) causes skin cancer
    • Mitigation - The ozone layer blocks a lot of the UV radiation
Paragraph 2
  • Paragraph note
    • A problem with the mitigation is explored
  • Views, minor Meta-Structures, and the author's attitude
    • 1970s - Two scientists show that CFCs are depleting the ozone layer
    • Lots of science
Paragraph 3
  • Paragraph note
    • A prediction is made and action is taken
  • Views, minor Meta-Structures, and the author's attitude
    • 1974 - 5 years of CFCs accumulated, problem will keep getting worse
    • Action - The 2 scientists become public advocates
Paragraph 4
  • Paragraph note
    • Outcome of action
  • Views, minor Meta-Structures, and the author's attitude
    • At first - Strong attacks by opponents, especially scientists at CFC companies
    • Turning point - Hole in ozone over Antarctica
    • Outcome - CFCs banned internationally
Main Point:
Because of the work of two scientists, the damage of CFCs to the ozone layer was recognized and then addressed by an international agreement.

Key Lines:
Lines 1-2 - A problem is introduced
Lines 3-6 - Something mitigating the problem is introduced
Lines 14-21 - A created problem with that mitigation is discussed, brought by 2 scientists
Lines 36-41 - A dire prediction is made
Lines 48-51 - An opposing point is made
Lines 51-53 - The view of the 2 scientists is vindicated
Lines 53-56 - The problem is addressed

Meta-Structure:
Problem/Solution - The passage has two levels of problems and solutions. The overarching problem is that UV radiation causes skin cancer (Lines 1-2), but that has a natural solution (Lines 3-6)—the ozone layer. However, humans have created a problem with that solution—according to 2 scientists, chemicals called CFCs are depleting the ozone layer (Lines 14-21). Their view is eventually vindicated (Lines 51-53), and a solution is put in place—an international ban on the production of the chemicals causing the problem (Lines 53-56).

Last Thoughts:
There was a whole lot of science in Paragraph 2. Don't try to understand/memorize it all. Instead, tag it, and head back to check details only when they're relevant to a question. You're not trying to earn a science degree here!

Question prompt

The information in the 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

Answer choices

  1. A
    What laboratory experiments were Remaining source text redacted.
    Why choice A is not credited
    Incorrect. (Lines 21-24) The passage discusses observations made by the two scientists of what happens in the troposphere and stratosphere, so there's no discussion of laboratory experiments.
  2. B
    What was the estimated Remaining source text redacted.
    Why choice B is not credited
    Incorrect. (Line 55) 1987 was the year of the Montreal Protocol, and there's no discussion of the estimated concentration of CFCs in the atmosphere at that time/in that paragraph.
  3. C
    In what year did Remaining source text redacted.
    Why choice C is not credited
    Incorrect. (Lines 44-45) The passage notes that Molina was called to testify, but it doesn't cite a specific year.
  4. D
    Does any chemical that Remaining source text redacted.
    Why choice D is not credited
    Incorrect. The passage discusses only CFCs, not other chemicals, so this answer is out of scope.
  5. E
    Which constituent element of Remaining source text redacted.
    Why choice E matches the stem
    Correct. Question Type:
    Must Be True

    Strategy Overview:
    Head straight to the answer choices and use our notes and the passage to find the correct one

    Answer Anticipation/Relevant Lines:
    The question stem here gives no guidance as to the topic of the correct answer, so we shouldn't spend a lot of time anticipating what will be correct. Instead, we should head straight to the answers and focus on the ones that line up with our overall understanding of the passage. When one lines up with that, we should use our notes and the passage itself to check to see if there's an answer to the question in the answer (yes, that's a confusing sentence).

    Answer Explanation:
    (Lines 25-26; Lines 26-28; Lines 31-33) This can be a tricky answer, as the passage never uses the word "most" and doesn't discuss other constituent elements. However, we're looking for a question that the passage "most helps to answer." The passage notes that CFCs break down into their constituent elements, including chlorine—it doesn't list any others. And it then states that chlorine is "devastating" to the ozone layer, destroying "as many as 100,000 ozone molecules" per chlorine atom. That makes a good case that chlorine is the most damaging constituent element of CFCs for ozone, so even though we can't answer this question with 100% certainty, we should feel comfortable selecting this answer.

    Key Takeaway:
    Note that, much like a Most Strongly Support Must be True question in LR, this answer is something that isn't proven with 100% certainty. However, the question stem asks us to find something that the passage "most" helps answer, and there's very strong language backing up answer choice (E) (e.g., "devastating").

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 12%
  2. B 4%
  3. C 5%
  4. D 8%
  5. E Credited 71%

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