#13 - A recent study concludes that prehistoric birds

[NeverMissing]

I got this answer correct, but I want to make sure my reasoning is correct. Since the question stem asks us to resolve the dispute between the two parties (in favor of one party), I knew that meant that we were looking for an answer that would simultaneously strengthen the conclusion of one theory while seriously weakening the other. The information about modern birds evolving from prehistoric birds in the stimulus was, I believe, a red herring. The point of dispute between the two parties is whether or not evidence shows that prehistoric birds were cold-blooded or warm-blooded. Modern birds do not factor into this.

The cold-blooded theorists believe that growth rings on bones of prehistoric birds indicate cold-bloodedness. In other words, they see evidence of growth rings on the prehistoric bones as being sufficient to being cold-blooded:

growth rings on bones cold-blooded

This reasoning is paralleled by the warm-blooded theorists. They see evidence of dense blood vessels as being sufficient to being warm-blooded:

dense blood vessels warm-blooded


Answer choice E states that in some cold-blooded species, a gene is responsible for the creation of both growth rings and dense blood vessels:

growth rings AND dense blood vessels cold-blooded

This premise is in conflict with the warm-blooded theorists, because it shows that a prehistoric bird can possess dense blood vessels and still be cold-blooded, thus making dense blood vessels alone not sufficient to determine warm-bloodedness. This bolsters the strength of the argument proposed by the cold-blooded theorists and weakens the argument proposed by the warm-blooded theorists. By doing this, answer choice E resolves the dispute in favor of one party.

Does the reasoning above follow logically? Thanks for indulging my explanation. I found this question tricky at first due to the phrasing of the question stem, and writing out the reasoning helped me understand it more fully!

[Emily Haney-Caron]

Hi NeverMissing,

AMAZING job on this! Your reasoning is spot-on, and I am incredibly impressed with the careful, thoughtful way you approached this question and the very clear way you explained your approach. If you keep taking that kind of time to work through questions that initially stump you, you are going to make huge improvements, because struggling through questions and sticking with it until they make sense really helps you learn. Keep up the good work!

[Christmaspuppy]

Hi! I read the comment of Nevermissing. I think his/her way to solve this question is absolutely incredible! But I am still confused by answer D.
Answer D: warm-blood animals don't have dense blood vessels
I think this answer choice also weakens the warm-blood theorists and strengthens the cold-blood theorists. Because answer D means that those prehistoric birds could be cold-blood animals. Since answer D and answer E both use some as their quantity word, I can't see why answer E is the answer which most help to resolve the dispute.

[Robert Carroll]

Christmaspuppy,

The issue with answer choice (D) is that no one is saying that all warm-blooded species have dense blood vessels. Some people are saying that ONLY warm-blooded species have dense blood vessels. So answer choice (D) is not relevant.

Robert Carroll

[Christmaspuppy]

Christmaspuppy,

The issue with answer choice (D) is that no one is saying that all warm-blooded species have dense blood vessels. Some people are saying that ONLY warm-blooded species have dense blood vessels. So answer choice (D) is not relevant.

Robert Carroll

Thank you Robert! Thanks for your patience! I can see where I made a mistake.