Individual elephants and Arctic herbivores such as caribou tend to have fixed geographic ranges throughout their lifetimes, which had prompted...
GMAT Craft and Structure : (Structure) Questions
Individual elephants and Arctic herbivores such as caribou tend to have fixed geographic ranges throughout their lifetimes, which had prompted some researchers to speculate that the Arctic woolly mammoth, an extinct elephantid, might have exhibited similar behavior. Mammoth tusks grew in sequential layers, incorporating ingested minerals and organics, and so each ivory stratum reflects the ratio of strontium isotopes (\(^{87}\mathrm{Sr}/^{86}\mathrm{Sr}\)) in the local environment; thus, the sequence of strata shows where the animal roamed during life. Recent analysis of the strontium ratios in the strata of one Arctic woolly mammoth tusk in relation to the geographic distribution of strontium ratios in the environment shows the animal's range begin to expand as it reached sexual maturity, only to contract again in its final 1.5 years.
Which choice best describes the function of the underlined statement in the text as a whole?
It discusses a characteristic shared by certain animals in order to explain why researchers raised a possibility that turned out not to be supported by data described later in the text.
It illustrates a pattern of behavior among certain animals in order to present a theory about exceptions to that pattern that is weakened by a finding described later in the text.
It describes a similarity in the behavior of certain animals in order to show why a method described later in the text did not reveal whether another animal also showed that behavior.
It introduces a trait shared by certain animals in order to contextualize a hypothesis about the origin of that trait that is advanced later in the text.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Individual elephants and Arctic herbivores such as caribou tend to have fixed geographic ranges throughout their lifetimes, which had prompted some researchers to speculate that the Arctic woolly mammoth, an extinct elephantid, might have exhibited similar behavior." |
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| "Mammoth tusks grew in sequential layers, incorporating ingested minerals and organics, and so each ivory stratum reflects the ratio of strontium isotopes in the local environment; thus, the sequence of strata shows where the animal roamed during life." |
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| "Recent analysis of the strontium ratios in the strata of one Arctic woolly mammoth tusk in relation to the geographic distribution of strontium ratios in the environment shows the animal's range begin to expand as it reached sexual maturity, only to contract again in its final 1.5 years." |
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Main Point: Analysis of mammoth tusks revealed that these animals had changing geographic ranges rather than the fixed ranges that researchers had speculated they might have based on modern elephant and caribou behavior.
Step 2: Interpret the Question Precisely
What's being asked? The function of the underlined statement within the overall text structure
What type of answer do we need? The rhetorical purpose or role this specific detail plays in supporting the passage's argument. Moderate language complexity
Any limiting keywords? N/A
Step 3: Prethink the Answer
- The underlined sentence establishes what we know about elephant and caribou behavior (fixed ranges) and explains that this knowledge led researchers to form a hypothesis about mammoths
- The later evidence actually contradicts this hypothesis since the mammoth had a changing range rather than a fixed one
It discusses a characteristic shared by certain animals in order to explain why researchers raised a possibility that turned out not to be supported by data described later in the text.
- Correctly describes the sentence as discussing a shared characteristic (fixed ranges)
- Properly identifies that this explains why researchers formed their hypothesis
- Accurately recognizes that the later data doesn't support this initial speculation
It illustrates a pattern of behavior among certain animals in order to present a theory about exceptions to that pattern that is weakened by a finding described later in the text.
- Mischaracterizes the content as presenting a theory about exceptions to that pattern when the sentence simply suggests mammoths might follow the same pattern
It describes a similarity in the behavior of certain animals in order to show why a method described later in the text did not reveal whether another animal also showed that behavior.
- Claims the method did not reveal whether mammoths showed the behavior, which is factually wrong since the tusk analysis clearly revealed the mammoth's movement patterns
It introduces a trait shared by certain animals in order to contextualize a hypothesis about the origin of that trait that is advanced later in the text.
- Says the sentence contextualizes a hypothesis about the origin of that trait, but the passage never discusses the origin of fixed ranges in any animals