I'm not sure I understand your question. The answer to this question is (A), not (B).
The app shows (A) as the correct answer. Your book shows (A) too. If there is something I am missing, please let me know.
The question asks, "Which one of the following most accurately describes the role played in the passage by the claim that nonmarine reptiles have scales?"
We know that the biologists the author agrees with do not think that marine reptiles were the first animals to develop the capacity for flight, and they provide support for their assertion by citing nonmarine reptiles with scales.
(A) says, "It is cited as evidence against the claim that the capacity for flight first developed in marine reptiles."
This is precisely what we said the phrase is doing; it's providing support for their claim, which is a rejection of the suggestion that the capacity for flight first developed in marine reptiles. (A) is the correct answer.
If you have additional questions, please let us know!
Faith-KunguMarch 7, 2019
my text book says the answer is A that's why it is little confusing. Thank you for the explanation
RaviMarch 12, 2019
@Faith-Kungu, I see, and you're welcome! Let us know if you have any other questions—we're here to help!
