#18 - Concept Reference, Must Be True, Subject Perspective

[Administrator]

Complete Question Explanation

The correct answer choice is (A).

Answer choice (A): This is the correct answer choice.

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E):


This explanation is still in progress. Please post any questions below!

[cmorris32]

Hello!

I just wanted to confirm that the proof for answer choice A is: "grew a random assortment of one billion different peptides" and "they developed additional related peptides from those that had the initially promising characteristics"?

I was apprehensive to choose answer choice A because I did not see that we could infer that some peptides did not previously exist in nature, but I couldn't find proof for answer choices A-D. Is this a valid inference because we know that Hu and Belcher grew and developed peptides?

Thank you in advance!!

[tonyking]

hello,
I have the same trouble for locating the evidence for A. Appreciate for any help, thx.

[Jeremy Press]

Hi cmorris and tony,

Yes, cmorris, that's exactly the portion of the passage where this inference is coming from! And there's even a little more to back it up than just the words "grew" and "developed." Look especially at the last sentence of the second-last paragraph, "[t]hrough a process resembling accelerated evolution, they developed additional related peptides from those that had the initially promising characteristics." Not only did they develop the peptides, they developed some of them "through a process resembling accelerated evolution." In other words, Belcher and Hu forced the peptides to undergo an evolution that would advance them (or at least change them) from the way they had existed previously. This is enough evidence to show that such peptides did not previously exist in nature (if they had existed, why would the researchers need to use a process resembling evolution to advance or change them?).

I hope this helps!

[lsatquestions]

I also found evidence in the last paragraph: "They are also designing new peptides that bind to two different crystals at once."

[Adam Tyson]

I'm not sure that's helpful in this question, since it asks us about the peptides they tested, not the new ones they are designing.