Reading comp PrepTest 107 · Section 2 · Question 17

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

Reiterate the main point as we summarized it after reading through the passage, then find the answer that best matches it.

Answer Anticipation

As discussed in the Meta-Structure section above, this passage utilizes a Phenomenon/Explanation Meta-Structure. In such a Meta-Structure, the main point is generally the author’s opinion of the explanation. In this passage, the phenomenon under discussion is the platypus’s ability to locate prey underwater. The author’s explanation for this ability is the function of the mechanoreceptors and electroreceptors located on the animal’s multi-functional bill, and the evidence the author uses to back up their explanation is the scientific studies of Bohringer, Scheich, and others. So the main point is: “New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater.”Let’s look for this information in the answer choices.

Answer choices

  1. A
    Neurophysiological studies have established Remaining source text redacted.
    Why choice A is not credited

    (A) Does this answer choice match our anticipation of the main point (“New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater”)?

    No. This answer choice expresses information that is an important building block in the author’s argument (P1 S4), but it is not the main point. The bill is indeed one of the platypus’s primary sensory organs, but it is the way in which the bill functions to enable the animal to locate prey underwater that is the crux of the point the author is making.

    This answer choice does not go far enough into the author’s argument to be the main point.

  2. B
    Neurophysiological studies have established Remaining source text redacted.
    Why choice B matches the stem

    (B) Does this answer choice match our anticipation of the main point (“New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater”)?

    Yes. This answer choice matches our anticipation of the main point very well. It does not mention Bohringer and Scheich by name, but it makes exactly the point that we thought it would make: explaining the platypus’s ability to locate prey underwater using scientific evidence of the function of its bill.

  3. C
    Bohringer's neurophysiological studies have Remaining source text redacted.
    Why choice C is not credited

    (C) Does this answer choice match our anticipation of the main point (“New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater”)?

    No. This answer choice is inaccurate and is trying to catch test-takers who didn’t read the passage carefully. Bohringer is the scientist who was looking at the mechanoreceptors (P1 S4), not the electroreceptors on the platypus’s bill.

    Because it is directly contradicted by the passage, this is not the right answer choice.

  4. D
    Biologists have concluded that Remaining source text redacted.
    Why choice D is not credited

    (D) Does this answer choice match our anticipation of the main point (“New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater”)?

    No. Again, this is a building block in the author’s argument, but it is not general enough to be the main point. The core of what the author is trying to do is to explain the platypus’s ability to sense prey underwater, and the fact that there are pores in the animal’s bill that contain mechanoreceptors and electroreceptors is a part of that explanation, but it is the function of those receptors that is critical to the explanation the author is trying to present.

  5. E
    Biologists have concluded that Remaining source text redacted.
    Why choice E is not credited

    (E) Does this answer choice match our anticipation of the main point (“New scientific research by Bohringer, Scheich, and others strongly suggests that the platypus uses its bill to locate prey underwater”)?

    No. This answer choice is, again, a building block in the author’s argument that helps explain the way in which the electroreceptors in the platypus’s bill function and allow it to locate prey, but it does not touch on the function of the mechanoreceptors, which are the subject of the other half of the passage.

    This answer choice is too specific to be the main point.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 18%
  2. B Credited 68%
  3. C 7%
  4. D 2%
  5. E 5%

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