PrepTest 122

[lcid:3586] Prep Test 122 LSAT — Reading Comp — S3 Reading comp

Passage

Questions 21-27  .        Every culture that has adopted the cultivation of  . maize—also known as corn—has been radically  . Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Background on corn/maize; Question about it; Answer previewed
  • Views, minor Meta-Structures, and the author's attitude
    • Corn/Maize - Reshapes cultures; primary reason = productivity
    • Question - Why so productive?
    • Answer - Biochemistry has found one

Paragraph 2

  • Paragraph note
    • Process of plants making carbs; limit to productivity (Problem)
  • Views, minor Meta-Structures, and the author's attitude
    • Process - Photosynthesis - Split water, release oxygen, use carbon dioxide
    • Rubisco is key enzyme
    • Problem - When oxygen levels high, it gets in the way of rubisco working

Paragraph 3

  • Paragraph note
    • Some plants have found Solution to limit
  • Views, minor Meta-Structures, and the author's attitude
    • Lots of science
    • Split oxygen (and other gases) from cells with rubisco
    • Carbon dioxide changed to C-4, which can enter cells with rubisco
    • Called C-4 photosynthesis
    • List - Sugar cane, rice, maize - all on list of most productive crops

Main Point: Maize’s very high productivity is the reason it has the power to transform cultures, and it’s high productivity is due to C-4 photosynthesis.

Key Lines?

Lines 10-11 - Why maize is important

Lines 15-16 - A question

Lines 16-18 - An answer is previewed

Lines 28-30 - An important part of a process

Lines 30-35 - A problem

Lines 36-38 - A solution, and an answer, all rolled into one!

Lines 45-47 - More details on solution/answer

Lines 57-61 - More details on (and a name for) the solution/answer

Meta-Structure?

Question/Answer - Sometimes, the LSAT makes it a bit easy to identify a Meta-Structure. Here, the passage presents a question - question mark and all! - at the end of Paragraph 1 (Lines 15-16). It asks why maize and some similar crops are so relatively productive. And immediately after, it tells us that it’s going to dive into an answer (Lines 16-18), for maize at least (“underlying maize’s impressive productivity”). When a passage falls into a Question/Answer Meta-Structure, the Author’s answer (or her opinion on a key answer) serves as the main point. Here, the Author spends the first half of Paragraph 2 talking about the general process plants use to create carbs and the second half talking about a problem that limits productivity. She then dives into what’s different about maize that allows it to be so highly productive in Paragraph 3, resolving that problem and providing an answer to the question - maize uses a C-4 photosynthesis process to split oxygen from rubisco, allowing it to be more productive. This is the Author’s answer to the question that kicked off the argument in the passage, so it should make up the main point, as summarized above.

Problem/Solution - The end of Paragraph 2 introduces a problem that limits plant productivity - too much oxygen interferes with rubisco, slowing down the key enzyme that allows plants to make carbs (Lines 30-35). The Author then discusses the biochemistry behind how maize (and similar crops) solve this problem, allowing them to be particularly productive - they segregate the oxygen from the rubisco using a process known as C-4 photosynthesis (Lines 45-47; Lines 57-61). When a passage falls into a Problem/Solution Meta-Structure, the Author’s solution serves as the main point. In this passage, the solution to the problem also constitutes the answer to the main question of the passage, reinforcing it as the main point, which is reflected in our summary, above. Note that capturing essentially the same idea in two Meta-Structures isn’t a problem - it just means that we can look for language reflecting either in big picture questions!

List - The passage lists three crops that use C-4 photosynthesis and are among the most productive crops in Lines 59-61. This reflects the question asked at the beginning, which referred to “maize and a few similar crops.” This is a very limited list, though, so it’s likely to - at most - be the focus of a single question. That said, be careful of not falling for a trap here. It’d be easy to think that these other crops are a part of the main point since they’re referenced in the question, but look at the Author’s answer in Lines 16-18 - it discusses only maize, so our main point could reference these crops, but it doesn’t have to.

Last Thoughts?

Wow...that’s a lot of science. When there’s this much science, we are going to get some questions that require us to digest it and repeat some details in the answer choices. However, there’s no way you can possibly actually remember all this stuff after reading, so make sure that your notes are strong enough that you can quickly find the relevant information. Things like causal chains or processes (how photosynthesis works, Lines 20-27; C-4 photosynthesis, starting in Line 50), elements that are noted as important (rubisco, Lines 28-30), and problems (Line 30 introduces one with “Unfortunately”) are some of the things to know where they’re located. You will go back to check your answers against these sections, so you might as well have a “Table of Contents” or “Index” for where to find them.

Question prompt

Assuming that all other 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

Review the limitation that was noted on photosynthesis and how the C-4 process solved it, then find an answer that presents a process that accomplishes something similar

Answer Anticipation

This is a tricky question stem to wrap our heads around and figure out an approach to, and it seems to require some scientific thinking, so we should take a few seconds to process it and break it down.It’s asking us to find a process that would give a species an advantage “similar to” the one that C-4 gives plants that use it. When we’re tasked with finding something “similar to” something else, we’re dealing with a Parallel Reasoning question.In this case, we want to find something similar to the C-4 process. What role did that process serve in the passage? It presented a solution that some plants have evolved to the limitations on their photosynthesis process. In other words, we’re looking for an answer that also addresses this limitation in a way other than C-4 does, so we should review the limitation and how C-4 addresses it.The limitation is stated in Paragraph 2, starting in Line 30 (“Unfortunately”). There, it’s stated that the problem happens when there’s too much oxygen in the leaf and it starts to interfere with rubisco. C-4 plants address this with a solution found in Paragraph 3 - they keep oxygen and rubisco separated.So let’s find an answer that brings up something else that would prevent oxygen from interfering with rubisco other than keeping the two separated.

Answer choices

  1. A
    Water is split into Remaining source text redacted.
    Why choice A is not credited

    (A) (Lines 41-43) We’d defer on this answer because it doesn’t discuss rubisco or oxygen levels, and it seems that if it’s correct, it’d require us to dive into the science more than we’d ever be asked to. That said, we can also see that this is already established as being the case for photosynthesis/plants in Paragraph 3, so it can also be actively eliminated.

  2. B
    An enzyme with which Remaining source text redacted.
    Why choice B matches the stem

    (B) (Lines 34-35) When we identified the problem that limited plant productivity, we said that it was because too much oxygen interfered with rubisco. If rubisco is replaced with a functionally equivalent enzyme that oxygen doesn’t interfere with, then that addresses the problem, so this is the correct answer.

  3. C
    The vascular structures of Remaining source text redacted.
    Why choice C is not credited

    (C) (Lines 47-50) Similar to (A), this answer doesn’t directly address oxygen and rubisco being separated - it talks about oxygen being excluded from a portion of the leaf, but it doesn’t say that that is where the rubisco is located. Second, it seems as if this answer reflects an element of the C-4 process, as stated in Paragraph 3!

  4. D
    The specialized chlorophyll–containing structures Remaining source text redacted.
    Why choice D is not credited

    (D) This answer doesn’t talk about oxygen or rubisco, so we can be pretty certain that it doesn’t guarantee the two are separated or that oxygen is prevented from interfering with the rubisco.

  5. E
    An enzyme that does Remaining source text redacted.
    Why choice E is not credited

    (E) (Lines 34-35) The passage notes that oxygen interferes with rubisco, not carbon dioxide, so this answer is incorrect.

What this tests

Discussion

  • Answer choice B 0 replies

    Started by amarachicynthia

  • Why not C 1 reply

    Started by Veda-Bhadharla

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