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# Networks of blood vessels in bats wings serve only

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Networks of blood vessels in bats wings serve only [#permalink]

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05 Dec 2005, 21:19
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16% (02:13) correct 84% (01:27) wrong based on 1409 sessions

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Networks of blood vessels in bats' wings serve only to disperse heat generated in flight. This heat is generated only because bats flap their wings. Thus paleontologists' recent discovery that the winged dinosaur Sandactylus had similar networks of blood vessels in the skin of its wings provides evidence for the hypothesis that Sandactylus flew by flapping its wings, not just by gliding.

The argument in the passage relies on which of the following assumptions?

A. Sandactylus would not have had networks of blood vessels in the skin of its wings if these networks were of no use to Sandactylus.
B. All creatures that fly by flapping their wings have networks of blood vessels in the skin of their wings.
C. Winged dinosaurs that flapped their wings in flight would have been able to fly more effectively than winged dinosaurs that could only glide.
D. If Sandactylus flew by flapping its wings, then paleontologists would certainly be able to find some evidence that it did so.
E. Heat generated by Sandactylus in flapping its wings in flight could not have been dispersed by anything other than the blood vessels in its wings.
[Reveal] Spoiler: OA

Last edited by Gnpth on 17 Aug 2016, 12:45, edited 1 time in total.
Updated the OA
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05 Dec 2005, 22:12
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Negate (B) and the argument falls apart. Just a little confused about "in the skin of the wings" and "in the wings".

(B)
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14 Dec 2005, 18:35
Why not (A) ?
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14 Dec 2005, 21:07
kdhong wrote:
Networks of blood vessels in bats' wings serve only to disperse heat generated in flight. This heat is generated only because bats flap their wings. Thus paleontologists' recent discovery that the winged dinosaur Sandactylus had similar networks of blood vessels in the skin of its wings provides evidence for the hypothesis that Sandactylus flew by flapping its wings, not just by gliding.

The argument in the passage relies on which of the following assumptions?

A. Sandactylus would not have had networks of blood vessels in the skin of its wings if these networks were of no use to Sandactylus.

the "networks of blood vessels" can have no usage or have usage ( and thus, must be the only use of dispersing heat generated in flight)
A eliminate the case in which the networks of blood vessels has no usage-----> the conclusion can be properly withdrawn.

I go for A.
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14 Dec 2005, 23:49
Another vote for A
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15 Dec 2005, 10:24
another vote for A.
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15 Dec 2005, 13:20
I will choose B.
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15 Dec 2005, 13:31
Another B.
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15 Dec 2005, 22:15
B certainly.
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15 Dec 2005, 22:50
'B' it is.
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15 Dec 2005, 23:18
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16 Dec 2005, 00:13
OA is A.
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16 Dec 2005, 05:09
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kdhong wrote:
OA is A.

i will try to explain.

let network of blood cells = x
heat dispersion = y
Sandactylus = z

its given that x can "only" do y. but its not given that y cannot be done any other way in a creature. its also given that z has x. and the conclusion is that in z, x does y.

it assumes that in z, y cannot be done any other way than x. and thus assumes that in z , x exists with a purpose and it is given that x has only one purpose that is y

hence A

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only if i could choose....

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16 Dec 2005, 05:11
i am still confused because what i said is already in E and my choice was E only.but i tried to justify the OA which is far indirect.
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28 Mar 2006, 18:23
Networks of blood vessels in bats' wings serve only to disperse heat generated in flight. This heat is generated only because bats flap their wings. Thus paleontologists' recent discovery that the winged dinosaur Sandactylus had similar networks of blood vessels in the skin of its wings provides evidence for the hypothesis that Sandactylus flew by flapping its wings, not just by gliding.

The argument in the passage relies on which of the following assumptions?

A. Sandactylus would not have had networks of blood vessels in the skin of its wings if these networks were of no use to Sandactylus.

B. All creatures that fly by flapping their wings have networks of blood vessels in the skin of their wings.

C. Winged dinosaurs that flapped their wings in flight would have been able to fly more effectively than winged dinosaurs that could only glide.

D. If Sandactylus flew by flapping its wings, then paleontologists would certainly be able to find some evidence that it did so.

E. Heat generated by Sandactylus in flapping its wings in flight could not have been dispersed by anything other than the blood vessels in its wings.
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28 Mar 2006, 20:50
It has to be between A and B.....Going with B.
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28 Mar 2006, 21:23
I choose A. "all creatures" in B is very strong phase.
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29 Mar 2006, 03:20
I would go with A.

B says that All creatures that fly by flapping their wings have networks of blood vessels in the skin of their wings. But passage actually assumes the reverse ie. creatures having blood vessels in the skin fly by flapping the wings.
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29 Mar 2006, 03:42
E...
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29 Mar 2006, 16:46
^ A ^

It does not necessarily mean that networks of blood vessels of Sandactylus serve only to disperse heat just like it is in bats. Just looking at the similarity between two kinds is not enough to make such a conclusion.
Re: Networks of blood vessels in bats wings serve only   [#permalink] 29 Mar 2006, 16:46

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