GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 26 Apr 2019, 08:55

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Methanogensis describes the formation of methane by microbes

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 10 Apr 2012
Posts: 268
Location: United States
Concentration: Technology, Other
GPA: 2.44
WE: Project Management (Telecommunications)
Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

Updated on: 19 Apr 2013, 11:33
3
8
00:00

Difficulty:

75% (hard)

Question Stats:

56% (01:54) correct 44% (02:12) wrong based on 547 sessions

### HideShow timer Statistics

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.
Manager
Joined: 10 Mar 2013
Posts: 112
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

19 Apr 2013, 11:25
A seems best ...
what is the OA and the source ?
VP
Status: Far, far away!
Joined: 02 Sep 2012
Posts: 1052
Location: Italy
Concentration: Finance, Entrepreneurship
GPA: 3.8
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

19 Apr 2013, 11:30
1
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...
_________________
It is beyond a doubt that all our knowledge that begins with experience.
Kant , Critique of Pure Reason

Tips and tricks: Inequalities , Mixture | Review: MGMAT workshop
Strategy: SmartGMAT v1.0 | Questions: Verbal challenge SC I-II- CR New SC set out !! , My Quant

Rules for Posting in the Verbal Forum - Rules for Posting in the Quant Forum[/size][/color][/b]
Intern
Joined: 05 Apr 2010
Posts: 12
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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.
Senior Manager
Joined: 10 Apr 2012
Posts: 268
Location: United States
Concentration: Technology, Other
GPA: 2.44
WE: Project Management (Telecommunications)
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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 .
Director
Status: Final Lap Up!!!
Affiliations: NYK Line
Joined: 21 Sep 2012
Posts: 864
Location: India
GMAT 1: 410 Q35 V11
GMAT 2: 530 Q44 V20
GMAT 3: 630 Q45 V31
GPA: 3.84
WE: Engineering (Transportation)
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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!!!!!!!!!!

Archit
Director
Status: Final Lap Up!!!
Affiliations: NYK Line
Joined: 21 Sep 2012
Posts: 864
Location: India
GMAT 1: 410 Q35 V11
GMAT 2: 530 Q44 V20
GMAT 3: 630 Q45 V31
GPA: 3.84
WE: Engineering (Transportation)
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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!!!!

Archit
VP
Status: Far, far away!
Joined: 02 Sep 2012
Posts: 1052
Location: Italy
Concentration: Finance, Entrepreneurship
GPA: 3.8
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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
_________________
It is beyond a doubt that all our knowledge that begins with experience.
Kant , Critique of Pure Reason

Tips and tricks: Inequalities , Mixture | Review: MGMAT workshop
Strategy: SmartGMAT v1.0 | Questions: Verbal challenge SC I-II- CR New SC set out !! , My Quant

Rules for Posting in the Verbal Forum - Rules for Posting in the Quant Forum[/size][/color][/b]
Intern
Joined: 01 Jul 2014
Posts: 19
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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.
SVP
Joined: 12 Dec 2016
Posts: 1534
Location: United States
GMAT 1: 700 Q49 V33
GPA: 3.64
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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.
Intern
Joined: 01 Jul 2016
Posts: 8
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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?
Current Student
Joined: 07 Jul 2010
Posts: 49
Location: Viet Nam
GMAT 1: 710 Q49 V36
GPA: 3.58
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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.
Intern
Joined: 01 Jul 2016
Posts: 8
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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

VP
Status: Learning
Joined: 20 Dec 2015
Posts: 1018
Location: India
Concentration: Operations, Marketing
GMAT 1: 670 Q48 V36
GRE 1: Q157 V157
GPA: 3.4
WE: Engineering (Manufacturing)
Re: Methanogensis describes the formation of methane by microbes  [#permalink]

### Show Tags

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.
_________________
Re: Methanogensis describes the formation of methane by microbes   [#permalink] 16 Jul 2017, 04:18
Display posts from previous: Sort by