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Scientists analyzing air bubbles that had been trapped in Antarctic ic

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Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 08 Dec 2009, 11:39
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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.
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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 10 Jun 2011, 11:29
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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.

Bubble revealed that air in ice-age had high ferrous content and very little carbon-dioxide.
Hypothesis: Ferrous material increased algae, which in turn absorbed CO2 from atmosphere. This theory explains a possible reason for low CO2 level.


Which one of the following, if true, would most seriously undermine the scientist’s hypothesis?
We need to weaken the hypothesis or prove it wrong.

A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age.
This information actually helps to a certain extent in corroborating the hypothesis. Since Diatoms didn't change much, it still traps CO2 as it during the ice age. Thus, at least the information about the CO2 trapping property of diatoms is not baseless. However, this statement doesn't undermine the hypothesis. It is more like a standalone fact.


(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae.
Something true today may not have been true in the past, esp. in ice age when temperature was extreme. Furthermore, this only strengthens the hypothesis that ferrous material might have caused the increase in algae.

(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material.
This is additional information that was not a part of the premise. May be it contained sulfur, zinc, aluminum; who cares if it did. So far it carried ferrous materials, the scientists' hypothesis holds good. If the statement said, "the bubble contained other minerals that neutralized the inherent properties of ferrous materials", then it could be a weakening statement. If we assume that these gases may have caused the algae, then we are assuming too much.

(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.

This statement may not be best in this world to weaken this hypothesis, but certainly is the best of the lot. It is attacking the hypothesis by finding out the fact that the algae's population didn't increase during the ice-age. Thus, the scientists hypothesis that increased population of algae caused the CO2 reduction is questionable.

Now, the scientists may come with a counter-argument that the tests used to actually analyze the sediment are rarely show correct results. Thus, despite your findings from the analysis of the sediments prove that the algae population didn't increase, it actually increased because your test findings are baseless.

Since we have to accept the statement as true, this directly casts a doubt on author's hypothesis.

It would be irrational to assume that the diatoms didn't die. If they didn't die, then they must still be present on the sea surface, making it easier for the scientists to hypothesize.

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.
Who said so that it would be harmed. Scientists said that the algae flourish in ferrous rich atmosphere. Strengthens part of the hypothesis.


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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 08 Dec 2009, 14:57
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IMO, Answer is D.

If the scientists did not find an increase in the number of shells that diatoms leave when they die, then clearly there was no increase in the algae and thus the scientists' hypothesis that the ferrous material in the atmosphere was responsible for the increase in algae is wrong!
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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 09 Dec 2009, 14:24
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C can't be the answer as the passage doesn't mention the impact of other minerals anywhere.
'D' is the best choice since it mentions that there was no significant increase in algae population, hence no reason to believe that it could be the reason for low concentrations of CO2.

IMO D.
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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 17 Dec 2009, 21:32
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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?
Brief: lots of ferrous material,BUT little CO2. Algae absorbs CO2. Conclusion: Scientist hypothesizes FM--> great increase in Algae.
A) Diatoms are a microscopic form of algae that has remained largely unchanged since the last ice age --> even though the diatoms are one type of artarctica algae, however, it is hard to strongly weaken the conclusion because it is just one kind of Algae. I consider this negligible weakening.
(B) Computer models suggest that a large increase in ferrous material today could greatly promote the growth of oceanic algae. -->strengthen
(C) The dust found in the air bubbles trapped in Antarctica ice contained other minerals in addition to the ferrous material. -->other minerals is out of scope.
(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. --> this suggests that there is no evidence that there are increase in shells which was died diatoms. So, no increase in diatoms. weaken. CORRECT
(E) Algae that currently grow in the oceans near ntarctica do not appear to be harmed by even a large increase in exposure to ferrous material. -->lightly strengthen

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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 10 Jun 2011, 09:54
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Although i understand D, I don't understand how to take out C.

The question says "if true" which means if you take the statements in the options to be true would it "most seriously" undermine the hypothesis.

How can C be out of scope or Irrelevant when the question itself brings it into scope when you view the argument and the option C as whole? The Scientist hypothesize that the ferrous material in the dust promoted the increase. If you get other minerals into the picture doesn't that question the hypothesis?

Please help clarify this.
Thanks.
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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 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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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 10 Jun 2013, 21:14
Answer D according to me.

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.
Talks about Diatoms, but not about "no increase whatsoever"

(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 :-D

(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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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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New post 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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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic  [#permalink]

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Re: Scientists analyzing air bubbles that had been trapped in Antarctic ic   [#permalink] 16 Jan 2019, 20:03
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