Reading comp PrepTest 124 · Section 4 · Question 25

Passage

Questions 20-27  .        Sometimes there is no more effective means of  . controlling an agricultural pest than giving free Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • A generalization and an example
  • Views, minor Meta-Structures, and the author's attitude
    • Generalization - Sometimes, best pest control is using a predator
    • Example - Cyclamen (Cyc) (pest)/Typhlodromus (Typh) (predator mite)
    • Usual cycle - Cyc infest, get out of control year 2, Typh move in and control them

Paragraph 2

  • Paragraph note
    • Features of Typh that make them work
  • Views, minor Meta-Structures, and the author's attitude
    • Hungry
    • Reproduction - method and rate (Similar to Cyc)
    • Seasonal and population densities
    • Reproduce only when there’s cyc
    • Similar - Other predators that can control prey

Paragraph 3

  • Paragraph note
    • Study - Typh works
  • Views, minor Meta-Structures, and the author's attitude
    • Study - Greenhouse experiments - Strawberries (one with both, one with just Cyc and insecticide)
    • Results - Just Cyc = out of control; Both = Cyc under control

Paragraph 4

  • Paragraph note
    • Study backed up in real world
  • Views, minor Meta-Structures, and the author's attitude
    • In study, insecticide more harm than good
    • Real-world studies show same thing
    • Average - Cyc population 25x with no predators

Main Point: In some cases, the most effective means of controlling an agricultural pest is by using its predator, as is exemplified by the Cyclamen/Typhlodromus relationship.

Key Lines?

Lines 1-3 - A generalization is presented

Lines 4-6 - A specific example is noted

Lines 15-16 - List of factors owing to effectiveness introduced

Lines 33-37 - Features generalized to other predators

Lines 37-40 - Studies verify generalization

Lines 52-54 - Studies backed up in real world

Meta-Structure?

Generalization/Example - This question is one of the best examples (pun intended) of the Generalization/Example Meta-Structures in the history of the exam. It starts out by making a very general - yet strong - statement about a particularly effective means of controlling a pest population. It then goes into “[a] case in point” that it spends the rest of the passage exploring. When this Meta-Structure is present, the main point is the generalization, and the correct answer to any main point question will generally reference the example, as well - though it sometimes doesn’t.

List - Paragraph 2 is a list of “several factors” that explain why Typh is such an effective predator and can keep Cyc in check. That paragraph even generalizes from Typh to other predators in the last sentence (Lines 33-37), which reinforces the Generalization/Example Meta-Structure above.

Similarities - Paragraph 2 has a lot of comparisons in its list of factors. There are similarities between Typh and Cyc that makes Typh such an effective predator, and similarities between Typh and other predators that show a pattern to what makes for an effective predator.

Last Thoughts?

Paragraph 2 is difficult. There are a lot of details in there, and so we should be sure to head back there for any question that talks about similarities, any of the individual points of comparison/factors, or anything that sounds sciency, as that paragraph is the scienciest paragraph in the passage (yes, we just made up those words).

Paragraph 4 is interesting - it takes the studies from Paragraph 3 and shows that they pan out in the real world. One inherent flaw in any study is that it doesn’t necessarily represent the real world, but this passage gets around that to an extent by showing that the results can be found outside of a lab setting.

Question prompt

The author mentions the Remaining source text redacted.
Why the credited answer is right

Credited answer: D

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

Question Type

Science

Strategy Overview

Review the role of the paragraph including Lines 20-23, then use that big-picture context to understand the role of the statement in question in its immediate context

Answer Anticipation

Lines 20-23 showed up in Paragraph 2, and that’s where the Author listed features that make Typh such an effective means of controlling pest populations, so the egg-laying ability of Typh and Cyc must relate generally to that.Looking at the immediate context, we can see that Lines 20-23 describe a full sentence, comparing the reproduction rates of Cyc and Typh. That’s just information, though, and not context for what it’s used to support. The previous line is about how the reproduction happens, so it sounds as if these two factual statements are supporting an even earlier statement.Checking out the sentence before these two, we see that the Typh population “can increase as rapidly as that of its prey.” Now that makes sense as something supported by the information about the egg-laying “rates” of each mite! By showing that a Cyc lays 3 eggs/day for 4-5 days (12-15 total), and a Typh can lay 2-3 eggs/day for 8-10 days (16-30 total), the Author is supporting this view that the predator population can go up at least as fast as the prey. Let’s find an answer reflecting that.

Answer choices

  1. A
    Mites that reproduce by Remaining source text redacted.
    Why choice A is not credited

    (A) This is a tricky trap answer. The Author does lead into the discussion of egg-laying ability with a discussion of parthenogenesis. However, there’s no transition between the two to suggest that they’re directly connected. This answer is also too broad, as the Author is speaking specifically to Cyc and Typh at this point in the paragraph. And, finally, the rates aren’t about the same - Cyc is 12-15 eggs total, while Typh is 16-30 total - the Typh lower end is higher than the Cyc higher end, and the Typh higher end is more than double that of Cyc!

  2. B
    Predatory mites typically have Remaining source text redacted.
    Why choice B is not credited

    (B) (Lines 20-23) The passage does establish that the Cyc reproductive lifespan is 4-5 days, compared to the longer 8-10 days of Typh. However, first, this information is specific to Typh, so this answer is too broad in stating that it’s about predatory mites generally. Second, since it supports the view that populations of Typh can increase as rapidly as Cyc, the reproductive life span doesn’t matter - what matters is the number of eggs laid during that time. If the Typh had a 2 days reproductive lifespan but could lay 30 eggs/day, that would also support the statement the Author included this information to support.

  3. C
    Typhlodromus can lay their Remaining source text redacted.
    Why choice C is not credited

    (C) (Lines 23-24) This answer is trying to get you to connect the egg-laying ability to the seasonal synchrony from the last line. However, seasonal synchrony would deal with when these eggs are being laid, not the rate at which they’re being laid.

  4. D
    Typhlodromus can reproduce at Remaining source text redacted.
    Why choice D matches the stem

    (D) (Lines 17-23) The paragraph kicks off by stating that it’s going to highlight several factors that let Typh be an effective predator of Cyc. The first factor is that its population can “increase as rapidly as that of its prey.” The rate that both lay eggs directly speaks to this relationship, so it serves as support for it, as this answer choice states. This answer is therefore correct.

  5. E
    The egg–laying rate of Remaining source text redacted.
    Why choice E is not credited

    (E) The comparison in Lines 20-23 doesn’t look at Typh when Cyc are around versus when they aren’t, and it never states that the variability is based on Cyc populations - it could just be natural variations between 8 and 10 days, and 2 or 3 eggs/day.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 6%
  2. B 9%
  3. C 23%
  4. D Credited 61%
  5. E 1%

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