The author would be most likely to agree with which one of the following statements?
Ceci_Perezon April 18, 2021
Why is A incorrect and B correct?
I narrowed the answer choices down to A and B, and ruled out B because it uses the word "flourishes", while the passage speaks in terms of "survives" - but I guess here it means essentially the same thing?
I was hesitant about A because it says "almost none", while the passage says "most attributes fall into neither [the harmful nor beneficial] category". However, it was still more attractive to me than B given the fact that in the second paragraph the author really hammers home the idea that most adaptations do not confer survival benefits. Most notably, the author says that "nonadaptive changes account to a large extent for the evolution of DNA".
While I understand that there is a difference between "almost none" and "less than half", the fact that the author says nonadaptive changes account to a large extent of DNA evolution, it seems like they are saying almost all adaptations are nonadaptive.
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To start, it is important to note that your final point is a bit of a stretch. We know that no adaptive changes account to a large extent for the evolution of DNA. This does not necessarily mean that most adaptations are no adaptive. All we can conclude is that no adaptive changes had a large influence on the evolution of DNA. It is entirely possible that most adaptations are not neutral but did not have as great an effect on the evolution of DNA as no adaptive changes.
Answer choice (A) is incorrect because it is too strong. We know from the passage that most attributes are neither harmful nor beneficial, but this does not necessarily mean that almost none of the characteristics of existing species were a result of natural selection. If this answer choice said that natural selection is responsible for some of the characteristics of existing species, then it would potentially be correct.
The support for answer choice (B) can be found in the final paragraph. We know from the composition of species on Earth today that mammals have flourished. We also know that mammals survived the mass extinction event that wiped out the dinosaurs. However, the passage clarifies that mammals could not have adapted to the conditions caused by the mass extinction event because these adaptations would have had to occur prior to the existence of the conditions which supposedly caused them. Therefore, the fact that mammals have flourished does not prove that they adapted to do so.
Hope this helps! Please let us know if you have any further questions.
Ceci_Perezon May 13, 2021
Awesome, thanks @victoria!! This makes a lot more sense now after your explanation
