SAT Reading & Writing · Text Structure and Purpose
Lizards living in cities have been found to have differences in limb length and toe-pad structure compared to their rural counterparts,…
Lizards living in cities have been found to have differences in limb length and toe-pad structure compared to their rural counterparts, differences that appear to improve their ability to grip broad, smooth artificial surfaces such as walls and pavement. Laboratory studies raising lizards from both environments under identical conditions found that some, but not all, of these differences persisted, suggesting the urban lizards' traits reflect a combination of inherited genetic change and flexible development in response to their environment.
Which choice best describes the function of the phrase "some, but not all, of these differences persisted" in the text?
Which choice best describes the function of the phrase "some, but not all, of these differences persisted" in the text?
Answer and explanation
Answer: C: It supports the passage's conclusion that both genetic and developmental factors likely contribute to the observed traits.
The phrase reports a mixed result, some traits held up under controlled conditions and some didn't, which is precisely the kind of evidence needed to support a "combination of" explanation instead of a single, all-or-nothing cause. C captures that connection directly. A overstates the finding into a complete denial of genetic involvement, when "some... persisted" actually supports a genetic component. B mischaracterizes the finding as contradicting the passage, when it directly supports the passage's stated conclusion. D misdescribes the phrase as a methodological detail instead of a substantive finding.
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