Reading Comprehension

PT107 · S2 · P3 · Q17 Platypus Bill

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Scientists have long known that the soft surface of the bill of the platypus is perforated with openings that contain sensitive nerve endings.

Topic

How the platypus uses its bill—specifically, touch and electroreception—to find prey underwater.

Framework

Old / New

Main Point

Scientists used to think the platypus’s bill was just touch-sensitive, but new studies reveal that it relies on both touch and electric signals to hunt underwater prey, since its eyes, ears, and nostrils are sealed while submerged. *Most Valuable Sentence*: (end of P1).

P1: Discovery of Bill Sensory Function

Scientists have long known that the platypus's bill is full of nerves, but only recently concluded that it is the primary way the animal finds food underwater because it can sense both touch and electrical signals. Bohringer's studies showed the bill is super sensitive to touch, but didn’t explain how it locates prey they can’t touch yet.

P2: Electroreception Revealed Through Experiments

Scheich’s research showed that platypuses hunt by detecting weak electric fields, just like some fish. His experiments (using a battery in water) made platypuses react as if food were present, showing they can sense electric fields from a distance—which led to the idea that the platypus hunts by sensing the electrical signals of its prey.

17.

Which one of the following statements best expresses the main idea of the passage?

  1. Neurophysiological studies have established that

    Wrong Emphasis: primary sensory organ

    Although this was said in the 1st paragraph, the main takeaway is supposed to be that "the bill of the platypus is used to locate prey underwater".

    18% picked this

  2. Correct

    Neurophysiological studies have established that

    Why this is right

    Okay, not too shabby! This aligns with our Most Valuable Sentence, which was adorned with two of the famous Purpose Pivots (but, yet, however, recently). Everything else in the passage was subsidiary to this headline. It elaborated on exactly how it is that the platypus uses its bill to locate prey underwater.

    Skill tested: Main Point · how this choice captures the passage's function is the move to repeat next time.

    67% picked this

  3. Bohringer’s neurophysiological studies have established

    Wrong Emphasis

    Wrong Emphasis: respond to stimulation Too Narrow: Bohringer Mismatched Scientists The passage is pretty well split between Bohringer and Scheich, so we wouldn't want our main point answer to only mention one of them. This answer fails to present the main discovery: the platypus uses its bill to locate prey underwater. Instead, it just presents a very minor narrow detail. It also botches the detail, in the sense that Scheich, not Bohringer, is the scientist who worked on electrical stimulation. Bohringer worked on tactile stimluation.

    5% picked this

  4. Biologists have concluded that the

    Wrong Emphasis: surface is perforated

    Although this was said in the 1st paragraph, the main takeaway is supposed to be that "the bill of the platypus is used to locate prey underwater". How does the platypus use its bill to locate prey underwater? Well, it starts with knowing that the surface of the bill is perforated with pores that contain two different types of receptors .... This answer is just presenting a subsidiary detail.

    2% picked this

  5. Biologists have concluded that the

    Too Narrow: just electric

    Although this was said in the 2nd paragraph, the main takeaway is supposed to be that "the bill of the platypus is used to locate prey underwater". Part of how it hunts prey underwater is picking up on their weak electric field to detect it at a distance. Once it picks up the electrical "scent", then it dive bombs the bottom of the water and starts throwing its bill around. From the 1st paragraph, we know that if the bill knocks up against anything, that tactile pressure induces the bill to start a snapping motion, to gobble up whatever is nearby. Like (D), this provides one subsidiary detail in the overarching story about the platypus using its bill to hunt prey underwater.

    9% picked this

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