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CR 1000 Test 27, Section II

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by TT » Fri Oct 12, 2007 7:25 pm
10. Insects can see ultraviolet light and are known to identify important food sources and mating sites by sensing the characteristic patterns of ultraviolet light that these things reflect. Insects are also attracted to Glomosus spiderwebs, which reflect ultraviolet light. Thus, insects are probably attracted to these webs because of the specific patterns of ultraviolet light that these webs reflect.
Which one of the following, if true, most strongly supports the argument?
(A) When webs of many different species of spider were illuminated with a uniform source of white light containing an ultraviolet component, many of these webs did not reflect the ultraviolet light.
(B) When the silks of spiders that spin silk only for lining burrows and covering eggs were illuminated with white light containing an ultraviolet component, the silks of these spiders reflected ultraviolet light.
(C) When webs of the comparatively recently evolved common garden spider were illuminated with white light containing an ultraviolet component, only certain portions of these webs reflected ultraviolet light.
(D) When Drosophila fruit flies were placed before a Glomosus web and a synthetic web of similar pattern that also reflected ultraviolet light and both webs were illuminated with white light containing an ultraviolet component, many of the fruit flies flew to the Glomosus web.
(E) When Drosophila fruit flies were placed before two Glomosus webs, one illuminated with white light containing an ultraviolet component and one illuminated with white light without an ultraviolet component, the majority flew to the ultraviolet reflecting web.
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Source: — Critical Reasoning |

by camitava » Sat Oct 13, 2007 12:46 am
TT, to me E is fine.
Because it compares between two Glomosus webs illuminated with white light - one with ultraviolet ray in it and another one without UV ray - and the flies were attracted to the first one.

TT what is the OA?
Correct me If I am wrong


Regards,

Amitava
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Ans....

by jangojess » Sun Oct 14, 2007 8:43 pm
A, B and C just mention that UV rays are reflected and so they partially support the conclusion. only D and E give effect of UV rays on insects, rest and b/w them E gives a comparison b/w UV and non-UV effects on insects..so ans shld be E...completely agree with camitava....
Trying hard!!!
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by samirpandeyit62 » Mon Oct 15, 2007 9:20 am
Agree it should be E
Regards
Samir
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by reply2spg » Sat Jul 31, 2010 8:21 pm
More than 2.30 minutes, E is correct
TT wrote:10. Insects can see ultraviolet light and are known to identify important food sources and mating sites by sensing the characteristic patterns of ultraviolet light that these things reflect. Insects are also attracted to Glomosus spiderwebs, which reflect ultraviolet light. Thus, insects are probably attracted to these webs because of the specific patterns of ultraviolet light that these webs reflect.
Which one of the following, if true, most strongly supports the argument?
(A) When webs of many different species of spider were illuminated with a uniform source of white light containing an ultraviolet component, many of these webs did not reflect the ultraviolet light.
(B) When the silks of spiders that spin silk only for lining burrows and covering eggs were illuminated with white light containing an ultraviolet component, the silks of these spiders reflected ultraviolet light.
(C) When webs of the comparatively recently evolved common garden spider were illuminated with white light containing an ultraviolet component, only certain portions of these webs reflected ultraviolet light.
(D) When Drosophila fruit flies were placed before a Glomosus web and a synthetic web of similar pattern that also reflected ultraviolet light and both webs were illuminated with white light containing an ultraviolet component, many of the fruit flies flew to the Glomosus web.
(E) When Drosophila fruit flies were placed before two Glomosus webs, one illuminated with white light containing an ultraviolet component and one illuminated with white light without an ultraviolet component, the majority flew to the ultraviolet reflecting web.
Sudhanshu
(have lot of things to learn from all of you)
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by crackinggmat » Sun Aug 01, 2010 9:00 am
E is good ...but how to prove D wrong....
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by selango » Sun Aug 01, 2010 9:30 am
Option D actually weakens the argument.The insects are attracted to Glomusus webs because they reflect some pattern of ultraviolet comp.This means insects are attracted to ultraviolet not particular kind of web.
If the insects are not attracted to synthetic web which also reflects the same ultraviolet component,then it weaken the argument that the insects are getting attracted to we b not ultraviolet component.

Option E provided additional support that Insects are attracted to ultraviolet component.
--Anand--
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