Reading comp PrepTest 122 · Section 3 · Question 23

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.

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

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.

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.