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# Methanogensis describes the formation of methane by microbes

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Methanogensis describes the formation of methane by microbes  [#permalink]

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Updated on: 19 Apr 2013, 11:33
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Methanogensis describes the formation of methane by microbes known as methanogens. The production of methane is often the final step in the decomposition of biomass, such as that found in cow manure. Clearly, therefore, by taking the resulting increase in methane levels in the atmosphere over the past decade and then determining how many decades of such increases it would have taken the atmosphere to reach current methane levels from a hypothetical initial methane-free state, the maximum age of the Earth's atmosphere can be accurately estimated.

Which of the following is an assumption on which the argument depends?

(A)The quantities of methane release into the atmosphere have not been unusually large during the past decade.

(B)At any given time, all layers of the atmosphere have about the same methane levels.

(C)There is methane that is released into the atmosphere from human activity, such as fossil fuel burning.

(D)There is no method superior to that based on methane levels for estimating the maximum age of the Earth’s atmosphere.

(E)None of the methane released into the Earth’s atmosphere is used up by plant activity.

I need some some help to answer this question . totally confused !!

Originally posted by guerrero25 on 19 Apr 2013, 11:17.
Last edited by guerrero25 on 19 Apr 2013, 11:33, edited 1 time in total.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 11:30
3
That's a good one, my answer is A.
The text says that "methane is often the final step in the decomposition of biomass" and they want to detemine the age of the earth " by taking the resulting increase in methane levels in the atmosphere over the past decade" and using it as a "scale".

This approch relies, generally speaking, on the uniformity of the methane during the years. If one period has had an unsual high level of methane then all the process will not be significant.
Now, basing my answer on this concept, I pick A:
(A)The quantities of methane release into the atmosphere have not been unusually large during the past decade.
As you can see A relies on the stats of the last decade, and if those are unusually high, the whole process is compromised.

There are also other good option as
(E)None of the methane released into the Earth’s atmosphere is used up by plant activity.
(C)There is methane that is released into the atmosphere from human activity, such as fossil fuel burning.
that could represent a good answer, but since we are talking about "the last decade", A (IMO) is better.

Waiting for OA...
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 11:25
2
A seems best ...
what is the OA and the source ?
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 13:22
2
E is close...bt its just stregthener nt an assumption.
Its already stated int he argument that we know the total amount of Methane generated. So the methane used up by the plants and other source may also have been taken into consider.

Hence A must be the answer...

Cosnider Kudos If my post helps!!!!!!!!!!

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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 11:36
1
Conclusion is that the method can be accurately used to estimate the maximum age of the atmosphere

Option A seems good. Keep it.
Option B is irrelevant. All layers having same levels cannot help us determine the levels of methane.
Option C is also irrelevant. Sources of methane will not help us estimate the levels for last decade.
Option D keep it for now.
Option E is also irrelevant with respect to the conclusion as it provides no information about methane levels.

Between A and D, used negation technique.
For D, There is a method superior…….. This does not attacks my conclusion.
For A, The quantities of methane have been usually large during past decade. Means now it can affect the data which is the basis for calculating the age. Attacks the argument and hence the right ans.

IMO A.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 13:41
1
guerrero25 wrote:
Zarrolou wrote:
That's a good one, my answer is A.
The text says that "methane is often the final step in the decomposition of biomass" and they want to detemine the age of the earth " by taking the resulting increase in methane levels in the atmosphere over the past decade" and using it as a "scale".

This approch relies, generally speaking, on the uniformity of the methane during the years. If one period has had an unsual high level of methane then all the process will not be significant.
Now, basing my answer on this concept, I pick A:
(A)The quantities of methane release into the atmosphere have not been unusually large during the past decade.
As you can see A relies on the stats of the last decade, and if those are unusually high, the whole process is compromised.

There are also other good option as
(E)None of the methane released into the Earth’s atmosphere is used up by plant activity.
(C)There is methane that is released into the atmosphere from human activity, such as fossil fuel burning.
that could represent a good answer, but since we are talking about "the last decade", A (IMO) is better.

Waiting for OA...

Zarrolou - could I have approached "A" by negating it ?

That means last decade did see an unusually large amount of methane released. If the statement is true then the increase over the last decade would be much larger than the usual increase. But, how is the argument going to fall apart ? Is it because the methane production during the years is going to be uniform ? That's not been stated ... Appreciate if you could shed some light .

Hi
I ll b happy if my post helps...
The argument states that u have to calculate a value fr last decade and use the same value fr approximation of the age of the earth. What if the value calculated fr last decade cannot be representative sample....

Hope that make sense
Consider kudos if my post helps!!!!

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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 13:45
1
guerrero25 wrote:

Zarrolou - could I have approached "A" by negating it ?

That means last decade did see an unusually large amount of methane released. If the statement is true then the increase over the last decade would be much larger than the usual increase. But, how is the argument going to fall apart ? Is it because the methane production during the years is going to be uniform ? That's not been stated ... Appreciate if you could shed some light .

If you negate A

(A)The quantities of methane release into the atmosphere have not been unusually large during the past decade.

The argument falls apart: it's clear that if you base your approach on unusual data, the conclusion will be flawed or weak.

Use a math-approach: if the levels of the last decade are NOT usual (as the case if we negate A), then calculus TOT/LastDecade will NOT give us a good info about the age of the earth. Only if the LastDecade number is correct, then the result will be correct.

Hope it's clear now, if not just send me a PM
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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19 Apr 2013, 13:15
Zarrolou wrote:
That's a good one, my answer is A.
The text says that "methane is often the final step in the decomposition of biomass" and they want to detemine the age of the earth " by taking the resulting increase in methane levels in the atmosphere over the past decade" and using it as a "scale".

This approch relies, generally speaking, on the uniformity of the methane during the years. If one period has had an unsual high level of methane then all the process will not be significant.
Now, basing my answer on this concept, I pick A:
(A)The quantities of methane release into the atmosphere have not been unusually large during the past decade.
As you can see A relies on the stats of the last decade, and if those are unusually high, the whole process is compromised.

There are also other good option as
(E)None of the methane released into the Earth’s atmosphere is used up by plant activity.
(C)There is methane that is released into the atmosphere from human activity, such as fossil fuel burning.
that could represent a good answer, but since we are talking about "the last decade", A (IMO) is better.

Waiting for OA...

Zarrolou - could I have approached "A" by negating it ?

That means last decade did see an unusually large amount of methane released. If the statement is true then the increase over the last decade would be much larger than the usual increase. But, how is the argument going to fall apart ? Is it because the methane production during the years is going to be uniform ? That's not been stated ... Appreciate if you could shed some light .
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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01 Mar 2016, 23:39
i was stuck btw A and C. n got it wrong. but after careful observation and consideration one can find that A is the answer. as if there is some unusual activity during the last decade which has led to increase in methane concentration will lead to wrong estimate of earth's age.
option of plant consuming methane gas-i think if it remains the same will not led to wrong estimation.
same for-if gas is released into atmosphere by human activity. if all these phenomena are usual it will not lead to wrong estimation of earth's age.
hope it clarifies the doubt.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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15 Jul 2017, 22:48
"final step" is an important word -> lesson: do not ever underestimate any information that backs up the main argument in the passage.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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15 Jul 2017, 23:25
i chose 'D' but im still not able to get how can we assume 'A'
can someone please explain again in detail?
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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15 Jul 2017, 23:57
GmatAssasin24 wrote:
i chose 'D' but im still not able to get how can we assume 'A'
can someone please explain again in detail?

Will try my best.

The first two sentences are purely background information so you could skip them. The important part lies in the final one, which is also the conclusion:

"Clearly, therefore, by taking the resulting increase in methane levels in the atmosphere over the past decade and then determining how many decades of such increases it would have taken the atmosphere to reach current methane levels from a hypothetical initial methane-free state, the maximum age of the Earth's atmosphere can be accurately estimated"

The author stated that the maximum age of Earth's atmosphere can be accurately estimated. How? By determining the current level of methane (M) and then, dividing M to the increase in methane level in past decade (V). After all, we will have accurate age of Earth's atmosphere (A). In other words, A = M/T, assuming the starting point is zero.

The key phrases here is "accurately estimated". (A) could be accurately estimated if and only if (M) and (T) are accurately determined and reasonably assumed.

Option A tells us that (M) is not unusual and thus, we could use (M) to determine A. Negating option (A) does shatter the conclusion.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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16 Jul 2017, 01:51
Thank you for this mathematical form of explanation

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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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16 Jul 2017, 04:18
Imo A
Negating A
If the amount of methane in atmosphere has increased at a greater pace in the last decade we can not therefore estimate earth's atmosphere age .
There it is the necessary assumption.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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27 Aug 2019, 19:20
Hi,

Why is E incorrect? can someone give me solid reason to eliminate it?
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Methanogensis describes the formation of methane by microbes  [#permalink]

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Updated on: 29 Aug 2019, 12:11
319537AM wrote:
Hi,

Why is E incorrect? can someone give me solid reason to eliminate it?

The reason option e is incorrect is that it in a away it says that the level of methane wasn’t decreasing( being used by plants) ie. not decreasing means 1)increasing- if this happens, surely there will fluctuations in the level of methane hence the maximum age could probably increase, hence it won’t be possible to accurately determine what we want to

2) remains the same : which means that we will be accurately determine what we want to..

Posted from my mobile device

Originally posted by INSEADIESE on 28 Aug 2019, 13:46.
Last edited by INSEADIESE on 29 Aug 2019, 12:11, edited 1 time in total.
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Re: Methanogensis describes the formation of methane by microbes  [#permalink]

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29 Aug 2019, 11:17
Even if some of it is taken up by plant activity, that can happen over decades and the plan to calculate the age of atmosphere may still work out. Hence E is incorrect. Option A/E are the only two contenders here.
Re: Methanogensis describes the formation of methane by microbes   [#permalink] 29 Aug 2019, 11:17
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