PrepTest 107

[lcid:3525] Prep Test 107 LSAT — Reading Comp — S2 Reading comp

Passage

Questions 16-21  .        Scientists have long known that the soft surface of  . the bill of the platypus is Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • New evidence from scientists including Bohringer shows that the platypus uses its bill to sense and snap at prey by while underwater.
  • Views, minor Meta-Structures, and the author's attitude
    • Platypus’s bill has sensitive nerve endings (first sentence)
    • Explanation of phenomenon: Platypus uses bill to locate prey while underwater (second sentence)
      • Eyes, ears, and nostrils sealed while underwater (second sentence)
    • New evidence: neurophysiological studies showed bill has mechanoreceptors, which detect touch, and electroreceptors, which sense electric fields (third sentence)
      • Bohringer: strength of input from mechanoreceptors indicates that bill is platypus’s primary sensory organ (fourth sentence)
        • Supported by studies showing touch on the bill induces snapping movement of jaws (fifth sentence)
      • These findings don’t explain how platypuses locate prey at a distance (sixth sentence)
      • Author’s attitude: “long known” (first sentence); “new evidence” (second sentence); “suggested by the fact” (second sentence); “recently revealed” (third sentence); “extraordinarily sensitive” (fifth sentence)

Paragraph 2

  • Paragraph note
    • The work of Scheich shows that platypuses use electroreceptors to locate prey at a distance via the weak electrical fields that the prey emit underwater.
  • Views, minor Meta-Structures, and the author's attitude
    • Schech’s studies: platypuses, when feeding, exhibit patrolling behavior until an electrical field is detected, then switch to searching behavior along the bottom of a body of water until they locate and seize prey (second-third sentences)
      • Hypothesis: platypus differentiates prey from other objects using electrosensory system (fourth sentence)
      • Scheich’s study: induced platypuses to switch from patrolling to searching behavior using a battery that emitted a weak electrical current (fifth sentence)
        • Platypus could detect and locate the battery at a distance of up to 30 cm (sixth sentence)
        • Platypus attacked battery as if it were food (seventh sentence)
      • Tail flicks of freshwater shrimp create an electric field similar to that emitted by the battery (eighth sentence)
        • Hypothesis: platypus’s common prey, underwater invertebrates, all emit electrical fields (ninth sentence)
      • Author’s attitude: “contribute to solving this mystery” (first sentence); “Scheich hypothesized” (fourth sentence); “rapidly oriented” (sixth sentence); “identical response” (eighth sentence); “reasonable to assume” (ninth sentence)

Main Point: New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater.

Key Lines?

Paragraph 1, Sentence 2 (P1 S2) - Thesis: platypus uses bill to locate prey underwater

P1 S3 - Bill has mechanoreceptors and electroreceptors

P1 S4 - Bohringer: bill is primary sensory organ

P1 S6 - Stimulating mechanoreceptors leads to snapping of bill

P2 S4 - Scheich: platypus senses prey at a distance using electroreceptors

Meta-Structure?

Phenomenon/Explanation: This passage uses a Phenomenon/Explanation Meta-Structure. The phenomenon under investigation is the ability of the platypus to locate prey while underwater. The author presents the hypothesis that the animal’s bill, which contains mechanoreceptors and electroreceptors and seems to be the only sensory organ in operation while the platypus is underwater, is the means by which it locates prey. The research and hypotheses of scientists Bohringer and Scheich is presented as evidence to support the author’s contention. Bohringer determined that stimulation of the mechanoreceptors on the platypus’s bill induced the jaws to snap, and Scheich showed that stimulation of the electroreceptors on the bill attracted the animal to the source of an electric current, suggesting that the platypus senses the weak electric fields emitted by prey.

The author seems to endorse the views of both Bohringer and Scheich, whose research is complementary and seems to explain the behavior and sensory abilities of the platypus.

Last Thoughts?

There are no hidden agendas in this passage. The author presents and tacitly endorses the views of two scientists, Bohringer and Scheich, and describes their experiments as evidence to back up an explanation of how the platypus senses prey underwater.

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

Strategy Overview

Consult notes to review the role of each paragraph in the passage, and choose the answer choice that best reflects those roles.

Answer Anticipation

After reading each paragraph, we should take a few seconds to note or reflect on its role. Doing so will help us track the author's argument, find details for questions, and directly answer Argument Structure questions like this one.Looking at our notes on each paragraph, we can see that the first paragraph uses the work of Bohringer to demonstrate that the platypus uses its bill to locate and snap at prey underwater, and the second paragraph uses the work of Scheich to demonstrate that the platypus uses its bill to locate prey at a distance using the weak electrical fields they emit. Together, the paragraphs support the overall main point that the platypus uses its bill to locate prey that is close by and prey that is further away underwater.Let’s look for language that echoes our map of the passage in the answer choices.

Answer choices

  1. A
    A hypothesis is presented Remaining source text redacted.
    Why choice A is not credited

    (A) Does this answer choice contain an accurate map of the passage, as we understand it?

    No. The passage does indeed present a hypothesis, that the platypus uses its bill to locate prey underwater (P1 S2), but it doesn’t use examples to support that hypothesis. It uses the results of scientific studies. The studies of Bohringer and Scheich are not examples, per se; they are demonstrations that help to prove the author’s point about the platypus’s abilities.

  2. B
    A conclusion is presented Remaining source text redacted.
    Why choice B matches the stem

    (B) Does this answer choice contain an accurate map of the passage, as we understand it?

    Yes. The passage does present its conclusion in P1 S2, and the information supporting this conclusion, namely, the results of the studies done by Bohringer, Scheich, and others, follow this conclusion.

    This is a simple description of the organization of the passage, but it is accurate, and we can be confident that it is the right choice, especially when we’ve compared it to the other choices.

  3. C
    A thesis is presented Remaining source text redacted.
    Why choice C is not credited

    (C) Does this answer choice contain an accurate map of the passage, as we understand it?

    No. The passage does begin with a thesis, namely, that platypuses use their bills to locate prey underwater (P1 S2), but it is hard to classify the information that follows as an “argument.” The information that the author uses to support their hypothesis is scientific data, and it is presented in a matter-of-fact way that does not make many assertions or claims. When the author does make claims, they are made in the form of hypotheses formulated by others (P1 S4, P2 S4, P2 S8), and not as something the author thinks.

    It is a subtle distinction, but, because of the way in which it is presented and the language that is used, the bulk of the passage can’t be correctly classified as an “argument.”

  4. D
    Opposing views are presented, Remaining source text redacted.
    Why choice D is not credited

    (D) Does this answer choice contain an accurate map of the passage, as we understand it?

    No. There are no opposing views presented in the passage. The work of Bohringer (P1 S4), Scheich (P2 S1-9), and others (P1 S3, P1 S5) is all complementary; the work of one scientist is totally consistent with, and even builds on, the work of the others mentioned in the passage. So there is no opposition or competition between views.

  5. E
    A theory is proposed, Remaining source text redacted.
    Why choice E is not credited

    (E) Does this answer choice contain an accurate map of the passage, as we understand it?

    No. A theory is certainly proposed, namely, that platypuses use their bills to locate prey underwater (P1 S2), it is considered in light of the studies of Bohringer (P1 S4), Scheich (P2 S1-9), and others (P1 S3, P1 S5), but it is not amended. The passage begins by stating that platypuses likely use their bills to locate prey underwater and that view is not countered, challenged, or changed by the end of the passage.

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