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Amphibian populations are declining in numbers worldwide.

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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  02 Sep 2010, 02:52
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It is not D. It is A.

D - If the natural habitat has not become small then it actually means that "lack of habitat" is not the reason and it kind of points out that UV rays might have well killed them despite the natural habitat being more or less intact.
A - It states the info already given. UV-B causes damage is a premise. A states that UV-B is the only radiation blocked by Ozone that causes damage. Even if it blocks any other radiation ... which causes cell damage, that info is not pertinent here.

Let me know if the explanation makes no sense.

Thank you.
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  02 Sep 2010, 06:31
E seems correct
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  06 Sep 2010, 10:39
A bit confusing
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  13 Jul 2011, 02:05
The answer can be obtained by POE.

(D) is incorrect because it strengthens the argument by eliminating another potential cause of the decrease in the amphibian populations.

However, it is interesting to understand why A doesn't strengthen the argument. Here's my reasoning:

(A) This answer does not strengthen the argument because:

- We know that ozone layer blocks UV-B radiation
- We know that amphibians are particularly vulnerable to UV-B radiation (i.e., they are not so vulnerable to other forms of radiation => other forms of radiation are not central to the well-being of amphibians).

Therefore, the fact that out of various forms of radiation blocked by the ozone layer UV-B is the only one that can damage genes adds nothing new to the argument (it only re-states that UV-B radiation is harmful to genes). Consequently, this information doesn’t strengthen the argument.
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  13 Jul 2011, 07:19
I am thinking on exactly the same lines as nandini11. Can anyone please explain why A and why not D?
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  25 Sep 2011, 03:05
hemanthp wrote:
It is not D. It is A.

D - If the natural habitat has not become small then it actually means that "lack of habitat" is not the reason and it kind of points out that UV rays might have well killed them despite the natural habitat being more or less intact.
A - It states the info already given. UV-B causes damage is a premise. A states that UV-B is the only radiation blocked by Ozone that causes damage. Even if it blocks any other radiation ... which causes cell damage, that info is not pertinent here.

Let me know if the explanation makes no sense.

Thank you.

Arigatho sensei!!....this really cleared things up for me..
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  26 Sep 2011, 06:21
huntgmat wrote:
Amphibian populations are declining in numbers worldwide. Not coincidentally, the earth’s ozone
layer has been continuously depleted throughout the last 50 years. Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that is continuously produced by the sun, and which can damage genes. Because amphibians lack hair, hide, or feathers to shield them, they are particularly vulnerable to UV-B radiation. In addition, their gelatinous eggs lack the protection of leathery or hard shells. Thus, the primary cause of the declining amphibian population is the depletion of the ozone layer.

Each of the following, if true, would strengthen the argument EXCEPT:
(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes.
(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from
UV-B.
(C) Atmospheric ozone has been significantly depleted above all the areas of the world in
which amphibian populations are declining.
(D) The natural habitat of amphibians has not become smaller over the past century.
(E) Amphibian populations have declined continuously for the last 50 years.

Tricky one
X --> Y (Premise, i.e. X causes Y)
If, we are given a statement that shows Z -->Y (i.e. Z also causes Y), then this statement will weaken the argument.
Hence OA should be A.
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  26 Sep 2011, 13:00
I love EXCEPT and LEAST Ques's..Thanks for posting...

In this type of ques we have 4 Strengthening Answer choices which are incorrect. And 1 Not strengthening choice( could be weakening or may have no impact on the stimulus).

Lets shoot the answer choices now........

Each of the following, if true, would strengthen the argument EXCEPT:

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. Oh this is the Correct one...It has no impact on the stimulus

(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from
UV-B. Strengthening

(C) Atmospheric ozone has been significantly depleted above all the areas of the world in Strengthening
which amphibian populations are declining.

(D) The natural habitat of amphibians has not become smaller over the past century. This is the sugar coated shell game answer

(E) Amphibian populations have declined continuously for the last 50 years.Strengthening
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  26 Sep 2011, 20:56
prateekbhatt wrote:
I love EXCEPT and LEAST Ques's..Thanks for posting...

In this type of ques we have 4 Strengthening Answer choices which are incorrect. And 1 Not strengthening choice( could be weakening or may have no impact on the stimulus).

Lets shoot the answer choices now........

Each of the following, if true, would strengthen the argument EXCEPT:

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. Oh this is the Correct one...It has no impact on the stimulus

(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from
UV-B. Strengthening

(C) Atmospheric ozone has been significantly depleted above all the areas of the world in Strengthening
which amphibian populations are declining.

(D) The natural habitat of amphibians has not become smaller over the past century. This is the sugar coated shell game answer

(E) Amphibian populations have declined continuously for the last 50 years.Strengthening

I would still go with E. Like other I was also split between A and E and chose E.

A still has impact on stimulus as : UV B damages genes ---> UV B is absorbed by ozone ----> when ozone is depleted, UV B will not be absorbed and hence the genes will be damaged.

I think E has no impact. E just states that the population has been declining for 50 years. reasons- dnt know. E is just stating a fact and fails to establish any relationship.

Am I going wrong somewhere??
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  27 Sep 2011, 11:29
GMATmission wrote:
prateekbhatt wrote:
I love EXCEPT and LEAST Ques's..Thanks for posting...

In this type of ques we have 4 Strengthening Answer choices which are incorrect. And 1 Not strengthening choice( could be weakening or may have no impact on the stimulus).

Lets shoot the answer choices now........

Each of the following, if true, would strengthen the argument EXCEPT:

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. Oh this is the Correct one...It has no impact on the stimulus

(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from
UV-B. Strengthening

(C) Atmospheric ozone has been significantly depleted above all the areas of the world in Strengthening
which amphibian populations are declining.

(D) The natural habitat of amphibians has not become smaller over the past century. This is the sugar coated shell game answer

(E) Amphibian populations have declined continuously for the last 50 years.Strengthening

I would still go with E. Like other I was also split between A and E and chose E.

A still has impact on stimulus as : UV B damages genes ---> UV B is absorbed by ozone ----> when ozone is depleted, UV B will not be absorbed and hence the genes will be damaged.

I think E has no impact. E just states that the population has been declining for 50 years. reasons- dnt know. E is just stating a fact and fails to establish any relationship.

Am I going wrong somewhere??

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes.

It is talking about diffrent UV B rays....And comparing all....Dosent strengthen the stimulus at all..Because we dont want to know what all UV B rays are dangerous...

Therefore does not have any impact on the stimulus.....
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Re: CR : Amphibian populations are declining in numbers worldwid [#permalink]  27 Sep 2011, 21:12
D really tricked me.

Its really A. Awesome-st Question.Loved it
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Re: Amphibian populations are declining in numbers worldwide. [#permalink]  22 Dec 2013, 22:24
Intresting question..Try it guyz..

I am comenting on this post, because, I want this question to be on top so that everyone cud try it !
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Re: Amphibian populations are declining in numbers worldwide. [#permalink]  22 Dec 2013, 23:33
Good question. My pick is A.

True. A has not effect on the arguments's strength. Whether UV-B rays are the only type that can damage genes is not necessary to conclude that the cause of the declining amphibian population is the depletion of the ozone layer.

In contrast D is strengthening. Had the natural habitat of amphibians become smaller over the past century, ozone depletion could not have been blamed for decline in the amphibian population.
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Re: Amphibian populations are declining in numbers worldwide. [#permalink]  23 Dec 2013, 05:10
Amphibian populations are declining in numbers worldwide. Not coincidentally, the earth’s ozone
layer has been continuously depleted throughout the last 50 years. Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that is continuously produced by the sun, and which can damage genes. Because amphibians lack hair, hide, or feathers to shield them, they are particularly vulnerable to UV-B radiation. In addition, their gelatinous eggs lack the protection of leathery or hard shells. Thus, the primary cause of the declining amphibian population is the depletion of the ozone layer.

Causal relationship- Depletion of ozone layer causes decline in amphibian population-
Assuption- 1. Depletion of ozone layer OCCURED before decline in amphibian population.
2. Nothing else caused the decline of amphibian population.
3. Decline in amphibian population did not cause Depletion of ozone layer
Strengthen could be any of the assumptions or evidences for the same or evidence proving premise - giving confidence on conclusion.
Assumption/ strengthener cannot just quote a premise already known.

Each of the following, if true, would strengthen the argument EXCEPT:
(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. Only states a premise . That is -UV-B can damage genes...NEITHER strenghthner NOR WEAKENER... so correct answer......
(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from
UV-B.Gives evidence that UV-B affect species whose tissues and eggs have lesser protection......hence strenghthner... so incorrect answer......
(C) Atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining. clear evidence...hence strenghthner... so incorrect answer......
(D) The natural habitat of amphibians has not become smaller over the past century. Means that the amphibians continue to live in areas where they used to...we can infer that LACK OF HABITAT DID NOT cause overall population decline......Hence strengthner so incorrect Answer.....
(E) Amphibian populations have declined continuously for the last 50 years. Since ozone depletion has occured since last 50 years....and amphibian population has declined in same duration-----ozone depletion must have caused it.....hence strenghthner... so incorrect answer......
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Re: Amphibian populations are declining in numbers worldwide. [#permalink]  23 Dec 2013, 08:31
The question stem asks us to look out for an option that does NOT strengthen the argument. Hence, that option could either weaken the argument to a certain degree or have no significant effect on it. Now let us examine each option carefully.
A) This option states that UV-B is the only type of radiation, among various types that are blocked by the ozone layer, that can damage genes. So what if it is the only type of such radiation? How does this fact further attribute the decline in amphibian population to the depletion of ozone layer? Lets keep this option.
B) The argument clearly states "their gelatinous eggs lack the protection of leathery or hard shells". Hence this is just one of the causes that have led to their decline which has been far more rapid than that of other non-amphibian species whose tissues & eggs have more natural protection from UV-B. We see that this option clearly strengthens the argument.
C) If atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining, then it certainly gives us reason to believe that this depletion may have caused the population decline. Hence this option too strengthens the argument.
D) if the natural habitat of amphibians has not become smaller over the past century, then it is almost certain that it is not a cause of the decline. Something else must have caused the decline. Hence this option too strengthens the argument.
E) If amphibian populations have declined continuously over the last 50 years during which the ozone layer has continuously depleted as well, as stated in the argument, the ozone layer depletion may have caused the decline. Hence this too strengthens the argument a bit.
Clearly then, (A) is the right option.
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Re: Amphibian populations are declining in numbers worldwide.   [#permalink] 23 Dec 2013, 08:31
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