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Networks of blood vessels in bats' wings serve only to disperse heat g

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Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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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.

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[Reveal] Spoiler: OA

Last edited by hazelnut on 01 Sep 2017, 20:43, edited 4 times in total.
Reformatted the question.

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 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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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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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

hope i made some sense :-)
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 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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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 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.

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 29 Mar 2006, 18:22
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SunShine wrote:
E...


I think E requires additional assumption that Sandactylus were also generation heat while flying.

B is 180 degree.

so the best answer is A.

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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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.

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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A says that Sandactylus used its network of blood vessels. 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. Based on this, I would say answer is A.
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 25 Sep 2006, 21:16
diegmat 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.

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.



I think its A

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.
It assumes that veins are there only for some purpose other than supplying blood. Negate it the argument falls apart. It provides a nuch clearer and a much broader assumption.

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.

This statement presupposes the assumption that Sandactylus flapps it wings and flapping might generate heat for Sandactylus and viens are there to cool them. So what do we negate here ? Do they flap their wings ? Do they generate heat if the flap ? Do they use their viens to cool their wings ? Negate each one , one by one and it doesn't do much harm to the argument as A.


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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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I am up for (A) too.
(E) says heat generated in flapping its wings(we havent yet established if sandalyctuses flapped their wings).
(B) is of the type
if A then B
therefore,if B then A(which is wrong)
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 30 Dec 2007, 09:48
diegmat 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.

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.


the argument says that the heat which is needed by networks is generated only by flapping wings, so if the dinosaurs would not have flapped their wings, the networks would be of no use

A. is coherent with the above
B. we do not know for sure if the dinosaurs flapped their wings
C. out of scope
D. not interesting for us
E. see B

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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diegmat 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.

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.

Great question. I now realise that it should indeed be A.

E is wrong:
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. IMO, there is nothing to suggest that heat is dispersed only by blood vessels. It says that blood vessels are there only to disperse heat, but this does not suggest the reserve is true.
Anyone disagrees?

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 08 Mar 2013, 10:51
Actual OG13 #84 has different question and answer stems. Here you go:


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.

In the passage, the author develops the argument by

(A) forming the hypothesis that best explains several apparently conflicting pieces of evidence
(B) reinterpreting evidence that had been used to support an earlier theory
(C) using an analogy with a known phenomenon to draw a conclusion about an unknown phenomenon
(D) speculating about how structures observed in present-day creatures might have developed from similar structures in creatures now extinct
(E) pointing out differences in the physiological demands that flight makes on large, as opposed to small, creatures









OA:C
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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diegmat 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.

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.


Responding to a pm:

This is not an easy question - especially if you are trying to explain the answer.
So first let's try to understand how the argument is structured. I will use variables to make it easier:

Networks of blood vessels in wings - A
heat generated in flight by flapping wings - B

Given Argument:
Bats have A. Bats have B. A's only job is to get rid of B.
Dinos had A too. Hence, Dinos had B too.

What is the assumption? That A must have had a purpose in Dinos too (getting rid of B). You cannot have A without having a job for it. Just because Dinos had A, we are concluding that they must have had B too. We are assuming that A must have had a purpose. This is option (A) and is the answer.

Are we assuming that we cannot get rid of B without A? No. (This is what option (E) says)
When would this be the assumption?
If the argument were a little different: Dinos had B. Hence, Dinos had A too.
In this argument, the assumption would have been that we cannot get rid of B without A.
But given the original argument, this is not the assumption. Hence, answer is not (E).
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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i can explain this to u like this though its difficult to parse in words
try and negate B : not All creatures that fly by flapping their wings have networks of blood vessels in the skin of their wings.
that means out of 100 creatures ,lets say, 95 falls into this category and 5 do not .so with this information u cannot be sure as into which category does this particular species fall( it might be in 95 category in that case the conclusion holds or it might be into 5 category and in that case the conclusion will fall apart ) and hence negating B is not making the destroying the conclusion
does it make sense ?

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 06 Nov 2013, 20:33
amkabdul wrote:
So we have 3 posts here each one saying: A is the OA; C is the OA and the Green color blinks on E

Great work guys...hope we get some vouchers for B and D to have cent percent successful attempts !!!!


The OA for the original question is (A).
Note that the post that says that the OA is (C) also tells you that OG has a different question stem (and hence a different answer) for the same argument.
Hence we are talking about two different questions on the same argument here and hence we have two different answers.

For some reason the original poster has given (E) as the OA in his original post which is incorrect. Perhaps a Verbal forum moderator will correct it.
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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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 Sandactytus.

(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 wingsin 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 findsome 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.

Last edited by carcass on 09 Apr 2014, 03:53, edited 1 time in total.
Edited the title of the question and formatted properly

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 08 Apr 2014, 20:25
Let us say these networks were of use to the dinosaur in such a way that these networks helped the dinosaur to to have flexible wings. Now that goes well with option A that says - 'andactylus would not have had networks of blood vessels in the skin of its wings if these networks were of no use to Sandactytus.'

But that doesn't necessarily prove the hypothesis that Sandactylus flew by flapping its wings, not just by gliding.

IMO E

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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 08 Apr 2014, 22:36
The argument makes an analogy between bats' wings and those of Sandactylus. The basic assumption is that if the Sandactylus had networks of blood vessels,it was solely due to flapping of wings. The correct option will be A.

You can also apply the negation test to the option and check.
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g [#permalink]

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New post 08 Apr 2014, 23:29
Between A & E

E- Supports that the Srus used to flap its wings any ways but had no mechanism to diesperse the heat but the blood vessels
A- Supports the conclusion that the Dino has blood vessels-->Hence it flapped its wings..As blood vessels did not serve any other purpose & neither were they redundant
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Re: Networks of blood vessels in bats' wings serve only to disperse heat g   [#permalink] 08 Apr 2014, 23:29

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