DAmaged nerves

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DAmaged nerves

by abby_g » Wed Oct 04, 2006 6:55 pm
Damaged nerves in the spinal cord do not regenerate
themselves naturally, nor even under the spur of
nerve-growth stimulants. The reason, recently dis-
covered, 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.

THe answer is A. Highlight to see the answer.

I couldn't solve this one. none of the answers are convincing to me. Can someone explain why the answer given is right.
Source: — Critical Reasoning |

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Re: DAmaged nerves

by 800guy » Tue Nov 07, 2006 6:45 pm
abby_g wrote:Damaged nerves in the spinal cord do not regenerate
themselves naturally, nor even under the spur of
nerve-growth stimulants. The reason, recently dis-
covered, 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.

THe answer is A. Highlight to see the answer.

I couldn't solve this one. none of the answers are convincing to me. Can someone explain why the answer given is right.
the key is to find the answer that weakens the argument. remember, the evidence that weakens doesn't have to be strong or extreme. finding the subtle answer is the strategy..

my choice is A). this is a really tough one, but i think it weakens the argument by saying that developing and using inhibitors in the body to regenerate nerves goes against normal human bodily function.

B) thru E) not relevant to argument that nerve repair will be standard in future

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Re: DAmaged nerves

by zipper123 » Wed Nov 08, 2006 11:54 am
abby_g wrote:Damaged nerves in the spinal cord do not regenerate
themselves naturally, nor even under the spur of
nerve-growth stimulants. The reason, recently dis-
covered, 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.

THe answer is A. Highlight to see the answer.

I couldn't solve this one. none of the answers are convincing to me. Can someone explain why the answer given is right.
Here are my 2 cents.
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 anit-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.
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by sibbineni » Sat Jan 19, 2008 7:07 pm
The answer is A ....


The conclusion says that antibodies can prevent the inhibitors and regeneration of nerves can be done naturally.


here we have to find out the which weakens the prediction


(A) says that preventing the damaged nerves to grow which exactly opposite of conclusion....

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by sibbineni » Sat Jan 19, 2008 7:09 pm
The answer is A ....


The conclusion says that antibodies can prevent the inhibitors and regeneration of nerves can be done naturally.


here we have to find out the which weakens the prediction


(A) says that preventing the damaged nerves to grow which exactly opposite of conclusion....

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by maihuna » Fri Jan 02, 2009 9:43 am
Nice post bad discussions...i coudnt really find the flaw with B: and point with A..I choosen B confirmed it is wrong not able to unearth the logic though...

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by amitabhprasad » Fri Jan 02, 2009 10:09 am
maihuna wrote:Nice post bad discussions...i coudnt really find the flaw with B: and point with A..I choosen B confirmed it is wrong not able to unearth the logic though...
Agree with maihuna
I selected "B" as well.
reasoning: antibodies
If nerve growth stimulants have chemical struct. similar to antibodies, then this automatically weakens the conclusion that antibodies will help regenerates nerve cell.

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by fighting_cax » Tue Feb 10, 2009 3:53 pm
Can we have more explanations on the OA please.

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by nawaab007 » Thu Mar 26, 2009 6:50 pm
Even I cant find a problem with B. A does not really sound convincing.

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Re: DAmaged nerves

by Ian Stewart » Fri Mar 27, 2009 8:48 am
The language here is quite dense, and a bit difficult to decode, but A is certainly the correct answer. We are looking for a reason to think that nerve repair will not become standard medical practice. The passage suggests that researchers have discovered an antibody to deactivate the inhibitors that have prevented nerve repair in the past. Answer A tells us that these inhibitors actually have a different function altogether - inhibiting nerve repair is not their primary purpose. If their other function is crucial to human survival, then deactivating these inhibitors will have severe consequences, so will not be a reasonable possibility.

B is not relevant, and is phrased in a similar way to many GMAT answer choices. Recall that you are never required to bring outside knowledge to a GMAT question. If two things have 'similar chemical structures', what conclusions can we draw? Unless some information about chemistry is provided in the question, none at all - perhaps two substances with similar chemical structures can behave very differently. This is true, in fact; Oxygen (O2) is required to sustain human life, while Ozone (O3) is toxic in reasonably small concentrations.
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by maihuna » Tue Dec 29, 2009 10:53 am
Ian Stewart wrote:The language here is quite dense, and a bit difficult to decode, but A is certainly the correct answer. We are looking for a reason to think that nerve repair will not become standard medical practice. The passage suggests that researchers have discovered an antibody to deactivate the inhibitors that have prevented nerve repair in the past. Answer A tells us that these inhibitors actually have a different function altogether - inhibiting nerve repair is not their primary purpose. If their other function is crucial to human survival, then deactivating these inhibitors will have severe consequences, so will not be a reasonable possibility.

B is not relevant, and is phrased in a similar way to many GMAT answer choices. Recall that you are never required to bring outside knowledge to a GMAT question. If two things have 'similar chemical structures', what conclusions can we draw? Unless some information about chemistry is provided in the question, none at all - perhaps two substances with similar chemical structures can behave very differently. This is true, in fact; Oxygen (O2) is required to sustain human life, while Ozone (O3) is toxic in reasonably small concentrations.
Good explanation Ian but can we say O2 and O3 are similar in structure :)
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by nikhilkatira » Fri Jul 30, 2010 2:28 am
Ian Stewart wrote:The language here is quite dense, and a bit difficult to decode, but A is certainly the correct answer. We are looking for a reason to think that nerve repair will not become standard medical practice. The passage suggests that researchers have discovered an antibody to deactivate the inhibitors that have prevented nerve repair in the past. Answer A tells us that these inhibitors actually have a different function altogether - inhibiting nerve repair is not their primary purpose. If their other function is crucial to human survival, then deactivating these inhibitors will have severe consequences, so will not be a reasonable possibility. can we have such assumptions ?
what if inhibitors always had negative effects ?


B is not relevant, and is phrased in a similar way to many GMAT answer choices. Recall that you are never required to bring outside knowledge to a GMAT question. If two things have 'similar chemical structures', what conclusions can we draw? Unless some information about chemistry is provided in the question, none at all - perhaps two substances with similar chemical structures can behave very differently. This is true, in fact; Oxygen (O2) is required to sustain human life, while Ozone (O3) is toxic in reasonably small concentrations.
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by pnk » Sat Jul 31, 2010 5:41 am
nikhilkatira wrote:
Ian Stewart wrote:The language here is quite dense, and a bit difficult to decode, but A is certainly the correct answer. We are looking for a reason to think that nerve repair will not become standard medical practice. The passage suggests that researchers have discovered an antibody to deactivate the inhibitors that have prevented nerve repair in the past. Answer A tells us that these inhibitors actually have a different function altogether - inhibiting nerve repair is not their primary purpose. If their other function is crucial to human survival, then deactivating these inhibitors will have severe consequences, so will not be a reasonable possibility. can we have such assumptions ?
what if inhibitors always had negative effects ?
Inhibitors can have either +ve or -ve effect; Since we do not have any information about whether inhibitors hv +ve or -ve effect, we can't say with certainity thta use of the antibodies can facilitate nerve repair.

Hope I have been able to articulate