#26 - Concept Reference, Strengthen

[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!

[mpoulson]

Hello,

Can you explain why the answer to 26 is A? How does this strengthen the overall argument? Is it because the research demonstrates that viruses can alter the DNA of an animal much Steele argued in work? I originally chose E thinking this shows the passage of acquired traits to the next generation. Why is this wrong specifically? Thank you.

[Ladan Soleimani]

Hi

Answer choice (A) is correct because it is an example of Steele's hypothesis happening with laboratory mice. Steele suggests that reproductive DNA can be changed by a virus that carries the new DNA to the reproductive cells. This is exactly what is happening in answer choice (A). The reason (E) doesn't strengthen is that the yolk sacs passing on immunities to gestating chicks, is not the same as the actual DNA being altered. In this answer the chicks DNA itself is not being changed.

I hope that helps!
Ladan

[LaCrosse]

May I offer a few additional thoughts on why (A) is right but (E) is not?

The question asks us to strengthen the position attributed to Steele and his colleagues, thus it’s important not to misinterpret what that position actually is. Per Lines 14-16: “he and his colleagues claim to have found evidence for a Lamarckian hereditary mechanism in the immune system”.
Though I failed to appreciate the distinction at first, that means that Steele’s position is not “Lamarck’s theory is right!”, it is the much more nuanced “We found evidence to support Lamarck’s theory”.

Lamarck’s theory is that “organisms change in adapting to their environment” (Lines 4-5) and that organisms can then “pass on to their offspring the new characteristics they have acquired” (Lines 5-7).

Steele explains his evidence this way: DNA can mutate (that’s already known), altered RNA reverts back into DNA (the “reverse transcription” that’s been observed frequently in other contexts), a virus carries the altered DNA to the reproductive cells and replaces the original DNA in those cells (other biologists aren’t yet sold on the last part).

Answer choice (A) strengthens Steele’s claim that he’s found evidence to support Lamarck’s theory. It does so by showing that the last part of Steele’s evidence chain (that other biologists have been quite skeptical about) can actually occur.

Answer choice (E) is wrong because it doesn’t strengthens Steele’s claim that he’s found evidence to support Lamarck’s theory. However, what (E) strengthens is Lamarck’s theory itself by providing an example of an organism that can pass on pass on an acquired characteristic to its offspring. How an organism does that (through DNA change or some other process) is irrelevant in regard to Lamarck’s claims. The danger with this question is that it’s very tempting to oversimplify Steele’s claim into being equivalent with Lamarck’s, making the wrong answer (E) seem very tempting.

[taylorharris24]

May I offer a few additional thoughts on why (A) is right but (E) is not?

The question asks us to strengthen the position attributed to Steele and his colleagues, thus it’s important not to misinterpret what that position actually is. Per Lines 14-16: “he and his colleagues claim to have found evidence for a Lamarckian hereditary mechanism in the immune system”.
Though I failed to appreciate the distinction at first, that means that Steele’s position is not “Lamarck’s theory is right!”, it is the much more nuanced “We found evidence to support Lamarck’s theory”.

Lamarck’s theory is that “organisms change in adapting to their environment” (Lines 4-5) and that organisms can then “pass on to their offspring the new characteristics they have acquired” (Lines 5-7).

Steele explains his evidence this way: DNA can mutate (that’s already known), altered RNA reverts back into DNA (the “reverse transcription” that’s been observed frequently in other contexts), a virus carries the altered DNA to the reproductive cells and replaces the original DNA in those cells (other biologists aren’t yet sold on the last part).

Answer choice (A) strengthens Steele’s claim that he’s found evidence to support Lamarck’s theory. It does so by showing that the last part of Steele’s evidence chain (that other biologists have been quite skeptical about) can actually occur.

Answer choice (E) is wrong because it doesn’t strengthens Steele’s claim that he’s found evidence to support Lamarck’s theory. However, what (E) strengthens is Lamarck’s theory itself by providing an example of an organism that can pass on pass on an acquired characteristic to its offspring. How an organism does that (through DNA change or some other process) is irrelevant in regard to Lamarck’s claims. The danger with this question is that it’s very tempting to oversimplify Steele’s claim into being equivalent with Lamarck’s, making the wrong answer (E) seem very tempting.

This is clarifying thank you!!

[WarnerHuntingtonIII]

Actually, I see now why A is better than E (I made the same mistake).

Look at it this way, what is the biggest flaw in the argument? The biggest flaw is that this hypothesis rests on circumstantial evidence about viruses being able to carry out this process. The last paragraph is like a giant spotlight on what's wrong.

So, how do we fix this giant flaw? Provide observable evidence that viruses can carry out this process. A does this. Ugh! So simple...

[Adam Tyson]

Egg-zactly, Warner! The evidence thus far is all circumstantial, so let's strengthen the hypothesis by providing empirical evidence. Let's see it happen! Nicely done.

[quan-tang@hotmail.com]

Hi

Answer choice (A) is correct because it is an example of Steele's hypothesis happening with laboratory mice. Steele suggests that reproductive DNA can be changed by a virus that carries the new DNA to the reproductive cells. This is exactly what is happening in answer choice (A). The reason (E) doesn't strengthen is that the yolk sacs passing on immunities to gestating chicks, is not the same as the actual DNA being altered. In this answer the chicks DNA itself is not being changed.

I hope that helps!
Ladan

Hi,
I still think E is better than A.

Because even though A describe how a virus can change reproductive DNA, the virus was directly injected by scientist, so it only solved half of the story, not proving a virus can arrive at reproductive cell from immune cell.

while E is a direct confirmation of it can happen.

[Luke Haqq]

Hi quan-tang!

Answer choice (E) certainly looks tempting.

However, one problem is that answer choice (E) isn't as specific as (A). Steele's views in the passage concern mutated DNA as a mechanism for Lamarckian inheritance. Answer choice (A) addresses that specifically, whereas (E) doesn't.

In addition, birds merely "pass[ing] on acquired immunities to their gestating chicks" isn't the same as mutating DNA. It's possible, for example, that the birds get a disease, develop an immunity to it, and then pass that immunity on to their chicks. But this says nothing of their chicks passing it down the germline to subsequent generations. That's something that mutated DNA would allow.