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Damaged nerves in the spinal cord do not regenerate themselves natural

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Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post Updated on: 10 Oct 2018, 03:36
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Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants. The reason, recently discovered, is the presence of nerve-growth inhibitors in the spinal cord. Antibodies that deactivate those inhibitors have now been developed. Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?


(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.

(B) Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors.

(C) Nerves in the brain are similar to nerves in the spinal cord in their inability to regenerate themselves naturally.

(D) Researchers have been able to stimulate the growth of nerves not located in the spinal cord by using only nerve-growth stimulants.

(E) Deactivating the substances inhibiting nerve growth for an extended period would require a steady supply of antibodies.


Source : Paper Test (Test Code 48)

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Originally posted by nitya34 on 19 Mar 2009, 00:45.
Last edited by Bunuel on 10 Oct 2018, 03:36, edited 2 times in total.
Renamed the topic and edited the question.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 30 Aug 2017, 15:53
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imawolf wrote:
mikemcgarry GMATNinja GMATNinjatwo carcass Could you kindly explain the logic behind answer choice A?

Dear imawolf,

My lupine friend, I am happy to respond. :-)

This is a brilliant question. I don't know the source.

Here's the prompt & question:
Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants. The reason, recently discovered, is the presence of nerve-growth inhibitors in the spinal cord. Antibodies that deactivate those inhibitors have now been developed. Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?


Here's (A), the OA:
(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.
That's a very complicated sentence. If you don't understand the term "by-product," you need to look that up and understand it thoroughly.

First, there are "substances inhibiting nerve growth" in the human body. Call these SING for short--an acronym.

The argument proposes using "antibodies" to "deactivate" the SING, to render them completely ineffective and non-functioning.

We may wonder whether "inhibiting nerve growth" is all the SING do or whether they have any other jobs.

Well, (A) tells us quite definitively that "Prevention of the regeneration of damaged nerves is merely a by-product of" SING. In other words, the SING have other jobs in the human body, their "main jobs," and "inhibiting nerve growth" is simply some that happens in addition to everything else they do. Each SING has a "main job" first, and "inhibiting nerve growth" is an extra that also happens--a by-product.

This piece of information presents a HUGE problem for the argument. We want to encourage nerve regrowth, but if we us antibodies to render the SING ineffective, then that will stop everything the SING do--it will stop all their "main jobs," as well as removing the blog to nerve regrowth.

Now, we don't know what those main jobs are, but the human body is truly miraculously designed. Three billion years of evolution have come together in producing a complex system so brilliantly interconnect and interrelated that it truly boggles our mind. Each body is a miracle packed full of a million miracles. Human beings walk around every day with no idea that their bodies are astonishing miracles beyond all reckoning.

If a substance in the body has a "main job," chances are very good that this "main job" is absolutely essential for the life and health of the body. Stopping this "main job" would have lead to dysfunction, illness, and perhaps even instant death!

Thus, shutting off the SING and their "main job" would produce devastating effects. Those side-effects are far too severe and dangerous, so this kind of treatment does not look promising after all.

Does all this make sense?
Mike :-)
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 13 Aug 2011, 13:33
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Our conclusion in this paragraph is "nerve repair will be a standard medical procedure in the forseeable future". We can imagine two instances were this would not be the case:

1) "Nerve repair" does not work - and there is therefore no reason to conduct the procedure.
2) "Nerve repair" will damage the body to such a degree, that the procedure will never be conducted (because of its byproduct), regardless of whether or not it regenerates nerves in the spinal cord.

Answer (A): This states that the main purpose of this inhibitor isn't to prevent regeneration of nerves, but something else entirely. Thus, we can conjecture that the main purpose is far more important than its secondary purpose of preventing regenration. Therefore, by turning off the inhibitor, we are possibly/probably causing collateral damage to the body.

(B) This esentially states that using other nerve-growth stimulants may have the same effect as injecting the antibodies. However, the effect would be the same, and therefore does not weaken the argument.
(C) This potentially strengthens (but certainly doesn't weaken) the argument that nerve repair will be a standard medical procedure in the future, as we can conjecture that the procedure might be possible on nerves found in both the brain and the spinal cord.
(D) The paragraph clearly states that those methods do not work on the spinal cord because of that inhibitor. This doesn't add any new information.
(E) This just tells you that the procedure is time-consuming/expensive. It doesn't negate the conclusion that we will be performing this procedure. (For example, chemotherapy is both a long and expensive treatment, but is still used in combatting cancer because of its effectiveness)
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 21 Mar 2009, 23:49
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I think it should be A, because
conclusion: Nerve repair would be a standard procedure
OptionA: Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.
This implies that there are many fiunctions of this substance apart from inhibitiion....So every time there is a procedure doctors should take care that other functions should not get affected and hence doctors cannot do the same thing for every patient evrytime. It will depend from patient to patient.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 27 Mar 2009, 06:26
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Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.

IMO A.

A says that new discovery is wrong. Hence no surety on probable effects.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 17 Feb 2011, 07:56
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Definitely, A.


(B) Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors. Not valid. This means that growth stimulants are antibodies. I don`t like the word "certain".
(C) Nerves in the brain are similar to nerves in the spinal cord in their inability to regenerate themselves naturally. - Not valid. We don`t care about nerves in the brain, we are talking about nerves in the cord
(D) Researchers have been able to stimulate the growth of nerves not located in the spinal cord by using only nerve-growth stimulants. Not valid. It doesnt`t correct to talk about other locations - there could be another types of nerves.
(E) Deactivating the substances inhibiting nerve growth for an extended period would require a steady supply of antibodies. So what??? Ok, let it be... We are talking about possibility, but not time period. So, irrelevant.

Actually, B, a bit confusing. It looks like a correct variant. But it is not.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 13 Aug 2011, 13:30
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Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future is the prediction given. However A states that :
Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.

This means that the main function may play vital role in the body and therefore prevent this from becoming standard medical practice. In regards to E, it is stated no where that antibiotics are in short supply so this does not weaken the conclusion.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 21 Feb 2013, 13:59
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I chose B and got this question wrong.
However, after review I think the answer is straight A.

Premise 1: Damaged nerves do not regenerate themselves naturally.
Premise 2: The reason is the presence of nerve-growth inhibitors.
Premise 3: Antibodies that deactivate those inhibitors have been developed.
Conclusion: Nerve repair will be a standard medical procedure in the foreseeable future.

Assumption: nerve-growth inhibitors are main factors that prevent damaged nerves' regeneration.

To weaken this assumption, we have to demonstrate those inhibitors are not the main factors, in fact, they are just by-products of the main function in the human body of the substances inhibiting nerve growth. So does that make any sense to attack the by-products. Nope!.

B is incorrect. Please see the first sentence: "Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants". It clearly says nerve-growth stimulants do not help to regenerate damaged nerves.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 02 May 2013, 14:07
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My take is A

Reason

A) If the prevention of nerve growth is just a by-product, it may disrupt other functions of the body when the anti-bodies were introduced to the body.
Thereby it would cast doubt over the possibility that nerve growth would become a standard procedure. Because this anti-bodies may have other unfavorable side effects.


B) Does not cast any doubt over the claim, because it would mean that there are more ways to encourage nerve growth beside the anti-bodies. Hence it supports the claim, that it will be a standard medical procedure.

C) Does not cast any doubt because the claim was that it will be a standard medical procedure. So this choice is suggesting that even the brain cells can be benefited from the anti-bodies would only increase demands of this procedure.

D) It supports the claim, because it means besides the anti-bodies, there is other means to make nerve repair be a standard medical procedure.

E) Since the question did not state that the anti-bodies are very limited, nor does it state any reason for it to be. This choice does not cast any doubt to the claim that it will be a standard medical procedure.

OA please..
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 12 Apr 2014, 01:37
CharuKapoor wrote:
Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants. The reason, recently discovered, is the presence of nerve-growth inhibitors in the spinal cord. Antibodies that deactivate those inhibitors have now been developed. Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?

(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.
(B) Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors.
(C) Nerves in the brain are similar to nerves in the spinal cord in their ability to regenerate themselves naturally.
(D) Researchers have been able to stimulate the growth of nerves not located in the spinal cord by using only nerve-growth stimulants.
(E) Deactivating the substances inhibiting nerve growth for an extended period would require a steady supply of antibodies.


(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.last man standing :)
(B) Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors. we are concerned abt the antiboides and not similar structured nerve growth stimulant
(C) Nerves in the brain are similar to nerves in the spinal cord in their ability to regenerate themselves naturally. we arent concerne abt nerves in brain
(D) Researchers have been able to stimulate the growth of nerves not located in the spinal cord by using only nerve-growth stimulants.we are not concernedabt nerver growth in areas other than spinal cord
(E) Deactivating the substances inhibiting nerve growth for an extended period would require a steady supply of antibodiesdosent weakens,still the antibodies are helpful
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 11 Jun 2016, 02:08
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Answer is A


Explaination :-

Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants. The reason, recently discovered, is the presence of nerve-growth inhibitors in the spinal cord. Antibodies that deactivate those inhibitors have now been developed. Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?

(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.
Some substance in your body has has some main function but it is also inhibiting nerve growth. Lets say that substance is vital such as insulin. Insulin is required for ATP metabolism, glucose and lipid transformations. Now no matter how many antibodies you give, insulin will be produced in your body, the moment even one molecule of glucose or fat enters your body. Now you can't avoid eating. You will die. So no doctor will carry such procedure. Another case. ASSUME serotonin an enzyme in brain that keeps you happy and prevent you from committing suicide is the inhibitor of nerve damage. You can suppress serotonin by chemically changing the brain chemistry by using medicines, but then the chances of your being forever depressed or killing yourself is high. So the procedure will not be standard but rare. hence A is right.

(B) Certain nerve-growth stimulants have similar chemical structures to those of the antibodies against nerve-growth inhibitors.
we are not talking about those certain growth stimulant , we are talking about a particular antibody.

(C) Nerves in the brain are similar to nerves in the spinal cord in their ability to regenerate themselves naturally.
It is a medical fact. But it is not relevant. All it is saying that brain cells also cannot regenerate naturally. In fact by using the same antibody we might actually regenerate them too.

(D) Researchers have been able to stimulate the growth of nerves not located in the spinal cord by using only nerve-growth stimulants.
Another fact. But we are concerned only about Spinal cord's nerves and Antibodies.

(E) Deactivating the substances inhibiting nerve growth for an extended period would require a steady supply of antibodies.
And a steady supply of antibody is quite easy to supply. Once the antibody is in market keep buying it. Whats the problem in that.

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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 30 Aug 2017, 07:46
mikemcgarry GMATNinja GMATNinjatwo carcass Could you kindly explain the logic behind answer choice A?
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural  [#permalink]

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New post 22 Apr 2018, 23:28
Problem: Damaged nerves in the spinal cord do not regenerate themselves naturally, even with the use of nerve-growth stimulants. Why? cause there are nerve-growth inhibitors. which means they are not letting body to regenerate nerves.

Solution: Antibodies that can deactivate inhibitors are discovered.

Conclusion: nerve repair will be a standard medical procedure in the foreseeable future.

Pre-think: For weaken the Conclusion, We have to look for an option that say it is not a good idea. or that it has some solid side effects.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?

(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances
inhibiting nerve growth. --- What is special about this choice is that is language is really complex. Lets decode. What this option really want to say is that these inhibitors have a different a specific requirement in body. one of those requirements is stopping the nerve-growth. if these inhibitors stopped doing its job, probably other body works can be hampered, may be some crucial one.

All other choices are irrelevant.
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Re: Damaged nerves in the spinal cord do not regenerate themselves natural &nbs [#permalink] 22 Apr 2018, 23:28
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Damaged nerves in the spinal cord do not regenerate themselves natural

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