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# Scientists analyzing air bubbles that had been trapped in

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07 Apr 2012, 11:19
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Premise: Scientists analyzing air bubbles that had been trapped in Antarctic ice during the Earth’s last ice age found that the ice-age atmosphere had contained unusually large amounts of ferrous material and surprisingly small amounts of carbon dioxide. One scientist noted that algae absorb carbon dioxide from the atmosphere.

Conclusion: ferrous material promoted a great increase in the population of Antarctica algae such as diatoms.

Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.
Only Diatoms has remained unchanged; other types of Algae may have increased - we do not know

(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae. - Strengthens the argument

(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.
Something else besides Ferrous material might be the reason

(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.
No increase in death; does that mean the population decreased? NO

(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material. No harm because of ferrous material but does it benefits the growth?

Only C is coming close to undermining the argument.
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03 Oct 2012, 00:10
Guys are saying that option D is within scope. I doubt!
This option describes a scenario near Antarctica. HOW COULD THIS BE CORRECT?
C correctly describes that there may be other minerals that might have been the reason behind the increase in population of algae.
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03 Oct 2012, 09:39
Scientists analyzing air bubbles that had been trapped in Antarctic ice during the Earth’s last ice age found that the ice-age atmosphere had contained unusually large amounts of ferrous material and surprisingly small amounts of carbon dioxide. One scientist noted that algae absorb carbon dioxide from the atmosphere. The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms.

Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.
talks about diatoms(population has remained unchanged) in general, not specifically about Antarctica region.
(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.
Incorrect - Strengthens the argument
(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.
The statement mentions that air bubbles contained other minerals but if other minerals caused increase in algae population is assuming too much for me. what if they were harmful...
(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.
specifically talks about diatoms population around Antarctica region. Correct.
(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material.
neutral or a weak strengthner because it says ferrous material is not harmful to algae population.
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26 May 2013, 12:55
vaibhav87 wrote:
Scientists analyzing air bubbles that had been trapped in Antarctic ice during the Earth’s last ice age found that the ice-age atmosphere had contained unusually large amounts of ferrous material and surprisingly small amounts of carbon dioxide. One scientist noted that algae absorb carbon dioxide from the atmosphere. The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms.

Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.

(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.

(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.

(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.

(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material.

Answer is C , in my opinion.
We need to undermine the scientists hypothesis that "ferrous material had promoted increase in algae" ...
OPtion C says , "there were couple of other stuffs found in the air bubbles trapped in the ice" , gives us a reason to believe that something else might have promoted an increase in algae - and hence doubt scientists hypothesis that ferrous is responsible for an increase.

Whereas, Option D , undermines the premise , but not the scientists hypothesis/conclusion. The premise says that there was an increase in algae then. D only lets us know that there might not be an increase in the algae back then . But we are not supposed to undermine the premise and rather are supposed to take it to be true. In this view, D does nothing to undermine the conclusion that "ferrous led to the increase in algae".

HTH
Jyothi
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10 Jun 2013, 21:14

Scientists analyzing air bubbles that had been trapped in Antarctic ice during the Earth’s last ice age found that the ice-age atmosphere had contained unusually large amounts of ferrous material and surprisingly small amounts of carbon dioxide. One scientist noted that algae absorb carbon dioxide from the atmosphere. The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms.

Summary: Scientists found that the atmosphere during the last ice age had large amounts of ferrous material and very less carbon dioxide. Explanation for very less carbon dioxide was that algae absorbed it.
Hypothesis: The increase in algae was because of the ferrous material.

Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?

Thought process: How can we weaken the Hypothesis?
Either we say the cause of the increase was not ferrous material, or we say there was no increase in algae whatsoever!
"No-increase-whatsoever" gives a lethal blow to the hypothesis!

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.

(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.
Says there was "definitely an increase!", thereby strengthening the argument.

(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.
Talks about "other minerals". This does not imply "other minerals caused the increase in algae." Close, but definitely not convincing enough to destroy the hypothesis

(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.
No increase in the mortal remains of algae! No increase in algae whatsoever! This is surely the answer

(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material.
Talks about algae of today and not about algae during the last Ice Age.

So answer according to me is D.
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11 Jun 2013, 07:46
vaibhav87 wrote:
Scientists analyzing air bubbles that had been trapped in Antarctic ice during the Earth’s last ice age found that the ice-age atmosphere had contained unusually large amounts of ferrous material and surprisingly small amounts of carbon dioxide. One scientist noted that algae absorb carbon dioxide from the atmosphere. The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms.

Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.

(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.

(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.

(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.

(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material.

In causality questions when argument say X cause Y I try to look 3 things
1) Maybe Y cause X
2)Something else cause Y
3) Y and X happens in the same time by coincidence

The argument states that The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms.
And in this example in C is looks like good example of Maybe not Ferrous material but something else may cause increase in algeas
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11 Jun 2013, 17:54
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vaibhav87 wrote:
(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.

(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.

Here's my take on these two:
C) There are a few materials; we hypothesize that ferrous material is the cause.
D) There has been a decrease in death, and thus there has unlikely been an increase in life.

"The scientist hypothesized that the ferrous material, which was contained in atmospheric dust, had promoted a great increase in the population of Antarctica algae such as diatoms"

For (C) to be correct, we are attacking the "ferrous material was the cause" issue.
For (D) to be correct, we are attacking the "increase in population" issue.

In my opinion, for those who say C is correct, you are in a way assuming that there was a - great increase - in the population, but that ferrous material was not the cause.

D is the correct answer because there could not have been a - great increase - in population with absolutely no change in mortality rate.
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13 Jun 2013, 00:32
Answer should be A, because here if we look at choice D, which says "sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated."
this choice shows no meaning to me, as weakening is concerned. as there is no increase in sediments, which points to shell that diatoms leave when they die.

As for A choice is concerned" Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age." Diatoms are unchanged, that is giving some counter to conclusion "great increase in the population of Antarctica algae such as diatoms.".
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12 Sep 2016, 15:04
atish wrote:
I think the answer is A.

The premises -
1) Large amounts of Ferrous materials found
2) Very little CO2 found
3) Algae absorb CO2

Conclusion
Ferrous materials caused an increase in Algae growth (There is no conclusive evidence to this).
The conclusion would be true if we knew either of the 2
A) Ferrous materials promote algae growth
B) The algae did increase in number thereby reducing the CO2 levels.

Now let us look at the choices
A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.
This statement negates Statement B above could be true.
(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.
Affirms statement A (incorrect).
(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.
Irrelevant
(D) Sediment from the ocean floor near Antarctica reflects no increase, during the last ice age, in the rate at which the shells that diatoms leave when they die accumulated.
Tempting choice as it might negate statement B, but if the amount of algea did increase it might also increase their lifespan thus not necessarily increasing their death rate. Since this doesn't directly negate statement B and we already have a choice (1) which directly negates it, we can safely assume it's incorrect.
(E) Algae that currently grow in the oceans near Antarctica do not appear to be harmed by even a large increase in exposure to ferrous material.
Indirectly supports statement A.

I also feel A is the right choice which clearly says that there is no increase of Algae.
Re: Scientists analyzing air bubbles that had been trapped in   [#permalink] 12 Sep 2016, 15:04

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