PrepTest 146

[lcid:3683] Prep Test 146 LSAT — Reading Comp — S4 Reading comp

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

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

Answer choices

  1. A
    No refrigerant chemicals other Remaining source text redacted.
    Why choice A is not credited
    Incorrect. (Lines 59-60) The passage notes that the outcome of M+R's work was "the development" of new refrigerants, which makes this answer tempting. However, those newly developed refrigerants are noted as being "environmentally friendly" ones—it's possible that other environmentally damaging refrigerants were already known, and that CFCs replaced them until their impact on the ozone layer was discovered.
  2. B
    Refrigerant chemicals developed as Remaining source text redacted.
    Why choice B 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:
    Similar to Questions #23 and #25, 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. From there, we can use our notes and the passage itself to check that answer.

    Answer Explanation:
    (Lines 59-60) The passage notes that the refrigerants developed after North American and then the world banned the use of CFCs were "more environmentally friendly." Since chlorine was the key element that caused CFCs to devastate the ozone layer, it must be the case that these new refrigerants release fewer chlorine atoms into the stratosphere. This answer is therefore correct. (And if you got hung up on "stratosphere," note what the passage says—the CFCs get released in the troposphere, float up to the stratosphere, and get hit with UV radiation, releasing their chlorine atoms there. In other words, the CFCs are released in the troposphere, but the chlorine atoms are released in the stratosphere.)

    Key Takeaway:
    Referring back to the last point, note that despite the large amount of science in this passage, you would have been 100% capable of answering the questions if the only science you took away from the passage was, "Chlorine is the really bad part of CFCs, as far as the ozone layer is concerned." Don't get too hung up on the science in a passage such as this one, as you're not likely to get many questions about it, and you'd head back to the passage to find the answer to those questions, anyway!
  3. C
    CFCs were originally used Remaining source text redacted.
    Why choice C is not credited
    Incorrect. There's no discussion of energy efficiency in the passage. Maybe they were used because they were cheap!
  4. D
    The Montreal Protocol led Remaining source text redacted.
    Why choice D is not credited
    Incorrect. (Lines 54-57) The passage pegs the Montreal Protocol to 1987 while North American banned their use in the 1970s. This answer reverses the timeline.
  5. E
    Some of the refrigerant Remaining source text redacted.
    Why choice E is not credited
    Incorrect. (Lines 59-60) This answer is a bit tricky! The passage notes that the refrigerant chemicals developed after CFCs were banned are "more" environmentally friendly. Doesn't that suggest that they're not entirely environmentally friendly? Nope—something that's free is cheaper than something that costs money—if we said, "Air is cheaper than bottled water," that's technically correct even though air costs nothing. So it's possible that the "more environmentally friendly" chemicals are completely environmentally friendly—or, at least, they're believed to be. Also, that line applies specifically to the chemicals made in the wake of the ban of CFCs. It's possible that they, too, have been replaced by other chemicals that are 100% environmentally sound, as far as we know.

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