It is currently 23 Sep 2017, 09:53

Happening Now:

Alleviate MBA app anxiety! Come to Chat Room #2


Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The optic nerves of identical twins are genetically identical.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Manager
Manager
User avatar
B
Status: Searching for something I've been searching..LOL
Joined: 14 Dec 2016
Posts: 55

Kudos [?]: 21 [0], given: 127

Location: India
Concentration: Healthcare, Operations
Schools: Ross '20
GMAT 1: 590 Q35 V42
GPA: 3.5
WE: Medicine and Health (Health Care)
CAT Tests
The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 18 Aug 2017, 23:09
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

51% (01:45) correct 49% (02:15) wrong based on 133 sessions

HideShow timer Statistics

The optic nerves of identical twins are genetically identical. When only one of a set of identical twins is visually impaired, certain areas of the affected twin’s optic nerve are atrophied whereas the corresponding areas of the other twin’s optic nerve is unaffected. No such differences are found when neither twin is visually impaired. Therefore, this discovery proves definitively that blindness is caused by damage to the structure of the optic nerve.

The argument above depends upon which one of the following?

A.The optic nerve of a blind person is smaller than that of anyone not suffering from visual impairment.

B.The relative size of the optic nerve of visually impaired individuals is not the result of corrective treatments or medications used to treat visual impairment.

C.The optic nerve of a person with an identical twin is no larger, on average, than the optic nerve of a person who is not an identical twin.

D.When a set of identical twins are both visually impaired, their optic nerves are in the same relative condition.

E.Individuals who have an identical twin are no more likely to suffer from visual impairment than are those who do not.
[Reveal] Spoiler: OA

Kudos [?]: 21 [0], given: 127

Intern
Intern
User avatar
B
Joined: 05 Feb 2017
Posts: 24

Kudos [?]: 9 [0], given: 22

The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 18 Aug 2017, 23:40
Conclusion :- Therefore, this discovery proves definitively that blindness is caused by damage to the structure of the optic nerve.
If there is any alternative cause,this would not hold.

Check option B
The relative size of the optic nerve of visually impaired individuals is not the result of corrective treatments or medications used to treat visual impairment.
Negate this and you will get an alternate cause which destroys the argument.
Therefore B is correct.

Kudos [?]: 9 [0], given: 22

1 KUDOS received
Intern
Intern
avatar
B
Joined: 15 Feb 2017
Posts: 29

Kudos [?]: 11 [1], given: 0

Re: The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 19 Aug 2017, 00:03
1
This post received
KUDOS
Conclusion :- Therefore, this discovery proves definitively that blindness is caused by damage to the structure of the optic nerve.
Option B :-The relative size of the optic nerve of visually impaired individuals is not the result of corrective treatments or medications used to treat visual impairment.
This option shows that the shrinkage of the optic nerve of impaired persons is not due to an alternate cause i.e Corrective treatments or medications used to treat visual Treatment. The alternate cause is ruled out. This premise strengthens the conclusion that blindness is caused by damage to the optic nerve,not any other reason. Please give me kudos . I need them badly

Kudos [?]: 11 [1], given: 0

Intern
Intern
avatar
B
Joined: 14 Feb 2017
Posts: 21

Kudos [?]: 5 [0], given: 3

GMAT 1: 630 Q50 V25
Reviews Badge CAT Tests
Re: The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 19 Aug 2017, 03:44
A. Irrelevant
B. Correctly assumes that gap between premises and the conclusion.
C. Irrelevant
D. This is not assumed but implied from the argument given.
E. Irrelevant

By assuming that the treatment of the visual impairment did not affect the optic nerve, it is clear that optic nerve plays a part in the visual impairment.

Kudos [?]: 5 [0], given: 3

Senior Manager
Senior Manager
avatar
G
Joined: 28 Mar 2017
Posts: 415

Kudos [?]: 103 [0], given: 117

Re: The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 19 Aug 2017, 13:53
The optic nerves of identical twins are genetically identical. When only one of a set of identical twins is visually impaired, certain areas of the affected twin’s optic nerve are atrophied whereas the corresponding areas of the other twin’s optic nerve is unaffected. No such differences are found when neither twin is visually impaired. Therefore, this discovery proves definitively that blindness is caused by damage to the structure of the optic nerve.

The argument above depends upon which one of the following?

A.The optic nerve of a blind person is smaller than that of anyone not suffering from visual impairment. -This is a fact set. Irrelevant

B.The relative size of the optic nerve of visually impaired individuals is not the result of corrective treatments or medications used to treat visual impairment. -Correct. This option removes the possibility of any alternate cause.

C.The optic nerve of a person with an identical twin is no larger, on average, than the optic nerve of a person who is not an identical twin. -This is a fact set. Irrelevant

D.When a set of identical twins are both visually impaired, their optic nerves are in the same relative condition. -This information is given in the premise. Even if this were to be correct, it doesn't give any information about the cause of blindness.

E.Individuals who have an identical twin are no more likely to suffer from visual impairment than are those who do not. -This is a fact set. Irrelevant

Kudos [?]: 103 [0], given: 117

Manager
Manager
User avatar
B
Status: Searching for something I've been searching..LOL
Joined: 14 Dec 2016
Posts: 55

Kudos [?]: 21 [0], given: 127

Location: India
Concentration: Healthcare, Operations
Schools: Ross '20
GMAT 1: 590 Q35 V42
GPA: 3.5
WE: Medicine and Health (Health Care)
CAT Tests
Re: The optic nerves of identical twins are genetically identical. [#permalink]

Show Tags

New post 19 Aug 2017, 23:23
This is a causal argument. Since the optic nerve in the blind twin is smaller than that in the twin with normal vision, the argument concludes that damage to the optic nerve is the cause of blindness. To weaken this argument, we need to assert either that there is some other cause, or that the causality is reversed. Answer B asserts that the causality could be reversed: the small size of the optic nerve might be the result of the treatments given to the blind child. Therefore, the correct answer is B.

Subject Area: Critical Reasoning

Categories: Weaken

Kudos [?]: 21 [0], given: 127

Re: The optic nerves of identical twins are genetically identical.   [#permalink] 19 Aug 2017, 23:23
    Similar topics Author Replies Last post
Similar
Topics:
2 EXPERTS_POSTS_IN_THIS_TOPIC People buy a message about their identities when they Nevernevergiveup 8 22 Sep 2017, 06:21
2 Millions of identical copies of a plant can be produced sudeep 6 17 Jul 2016, 13:56
6 My five-year-old identical twins wear matching clothing. shagalo 8 21 Aug 2017, 03:14
5 Identical twins tend to have similar personalities; if perfectstranger 9 23 Jul 2016, 11:34
13 EXPERTS_POSTS_IN_THIS_TOPIC The brains of identical twins are genetically identical souvik101990 10 21 Aug 2017, 07:01
Display posts from previous: Sort by

The optic nerves of identical twins are genetically identical.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.