Geologist: The dominant view that petroleum formed from the fossilized

Question

Geologist: The dominant view that petroleum formed from the fossilized remains of plants and animals deep in the earth's crust has been challenged by scientists who hold that it formed, not from living material, but from deep carbon deposits dating from the formation of the earth. But their theory is refuted by the presence in petroleum of biomarkers, molecules indicating the past or present existence of a living organism.

Which one of the following, if true, most weakens the geologist's argument?

Which one of the following, if true, most weakens the geologist's argument?

(A) Fossils have been discovered that are devoid of biomarkers.
(B) Living organisms only emerged long after the earth's formation.
(C) It would take many millions of years for organisms to become petroleum.
(D) Certain strains of bacteria thrive deep inside the earth's crust.
(E) Some carbon deposits were formed from the fossilized remains of plants.

Source: LSAT

broall · Accepted Answer

(A) Fossils have been discovered that are devoid of biomarkers.
 This choice is irrelevant to the argument

(B) Living organisms only emerged long after the earth's formation.
 This choice strengthens the argument. This choice supports the argument that petroleum formed from the fossilized of living material.

(C) It would take many millions of years for organisms to become petroleum.
 This choice strengthens the argument.

(D) Certain strains of bacteria thrive deep inside the earth's crust.
 Correct. This choice points out a possible case that could undermine the argument: There are some certain strains of bacteria, which led to the presence in petroleum of biomarkers, thrive deep inside the Earth's crust. On the other hand, the presence in petroleum of biomarkers is from the external factors, not from the petroleum source itself

(E) Some carbon deposits were formed from the fossilized remains of plants.
 This choice strengthens the argument since this choice indicates that the carbon deposits, which formed petroleum , were formed from the living materials.

david2099 · Answer

Option D. because the bio-markers, geologist is talking about, can be from the bacteria molecules within the earth crust.

gmatexam439 · Answer

Hi,

Could you please elaborate your answer? Bacteria are living creatures only. So, why did you choose D?

Regards

kunalsinghNS · Answer

broall  can you explain this one ? :/

gmatexam439 · Answer

Hi  broall ,
Thanks for the quick reply. I still have the following doubt:
As per the highlighted portion, we need to undermine the position that petroleum is formed from the fossils of living materials such as plants and animals.
Bacteria are also living creatures, then how does option D weaken the argument?

Please throw some light on this.
Regards

kunalsinghNS · Answer

Thank You for the prompt reply  broall 
but i have a question

How can you conclude that bacteria leads to the formation of biomakers, since nothing is mentioned in the argument ? plus bacteria are living organisms :/
can you explain this part ?

broall · Answer

You take the wrong argument. The argument is highlighted. Hope this helps!

The argument doesn't mention anything about bacteria, but this answer choice does. This choice provides some extra information that does weaken the argument.

gmatexam439 · Answer

Still not convinced with the answer. Bacteria are living organisms that definitely indicate the past/present of the living species.

Mahmud6 · Answer

Geologist's Argument:  Their (scientists') theory is refuted  by the presence in petroleum of biomarkers, molecules indicating the past or present existence of a living organism.

Scientists' theory is refuted. So, what is scientists' theory? Scientists' theory is that petroleum is formed from deep carbon deposits. So if scientists' theory is refuted, it becomes that petroleum is NOT formed from deep carbon deposits. Why? because the presence of molecules, the biomarkers, in petroleum.

We need to weaken the argument. We can do this by showing that  petroleum is formed from deep carbon deposits  or by showing that  the presence of molecules in petroleum does not necessarily lead that petroleum is NOT formed from deep carbon deposits.

Only option D weakens the argument by saying that the presence of biomarkers in petroleum may be from the external factors, not from the petroleum source itself (broall).

Akshay2402 · Answer

is option c strengthening the argument?
and how option D is weakening ?

GMATNinja · Answer

The passage sets up two conflicting views:

The dominant view: “petroleum formed from the fossilized remains of plants and animals deep in the earth's crust”  versus 
The view of certain scientists: “  formed, not from living material, but from deep carbon deposits dating from the formation of the earth”

After setting up these conflicting views, the geologist makes his/her main argument: the scientists’ theory “is refuted by the presence in petroleum of biomarkers, molecules indicating the past or present existence of a living organism.”

So, the geologist’s main point is that some evidence (the presence of biomarkers) goes  against  the scientists’ view. It does so by  supporting  the “dominant view” -- essentially, the geologist says “Look, there are biomarkers in petroleum that indicate the presence of living beings. This shows that petroleum formed from fossilized plants/animals, and that the other scientists were wrong.”

The question asks us which answer choice weakens the geologist’s argument.

First, take a look at (D): 
 
Hmm. The geologist used those biomarkers to support the idea that petroleum came from  fossilized plants/animals . (D) opens up another possibility -- maybe those biomarkers were actually just remnants of  bacteria  in the earth’s crust.

In that case, the geologist’s evidence is thrown into doubt -- perhaps the other scientists are right after all, and petroleum came from deep carbon deposits in which some bacteria happened to thrive. This means that the scientists’ theory would NOT be refuted by the biomarkers, and overall the geologist’s argument would be greatly weakened. (D) is the correct answer.

The geologist supports the view that petroleum formed from fossilized plants/animals, but he/she never mentions a timeline for this conversion process. (C) tells us that this transformation would take “many millions of years,” but that is totally compatible with the geologist’s claim.

(C) doesn't weaken the geologist's claim, so you can get rid of it.

I hope that helps!

auradediligodo · Answer

Geologist: The dominant view that petroleum formed from the fossilized remains of plants and animals deep in the earth's crust has been challenged by scientists who hold that it formed, not from living material, but from deep carbon deposits dating from the formation of the earth. But their theory is refuted by the presence in petroleum of biomarkers, molecules indicating the past or present existence of a living organism.

Which one of the following, if true, most weakens the geologist's argument?

Which one of the following, if true, most weakens the geologist's argument?

Weaken question

Pre-thinking

Common view:  Petroleum originates from animal and plants

Scientists' view:   Petroleum does not come from living organisms but from carbon

So the author claims that the scientists are wrong because in the petroleum biomakers are present.

In order to weaken the argument we should find an explanation that justifies the presence of biomakers in petroleum without strengthening the common belief.

POE:

(A) Fossils have been discovered that are devoid of biomarkers.
 Irrelevant

(B) Living organisms only emerged long after the earth's formation.
 no impact on the argument

(C) It would take many millions of years for organisms to become petroleum.
 the how aspect is irrelevant here

(D)   Certain strains of bacteria thrive deep inside the earth's crust.
 This is a good candidate. It is important to stress that the fact that bacteria are living organisms does not go against the scientists' belief since for what we know bacteria do not contribute to petroleum formation and are inside of it by chance

(E) Some carbon deposits were formed from the fossilized remains of plants.
 This option is wrong because now we have a petroleum composed both by elements of the common belief and by elements of the scientists' belief. Now we cannot choose a stand. Choice D on the other hand talks about an entity which is outside of the elements thought to make petroleum in the common belief.

canaguynotname · Answer

This is an argument weakening question. So the target is to find out a contradictory evidence (from the options) which points towards the existence of biomarkers in organisms that might have existed deep inside the Earth.

ArtVandaley · Answer

Easy one.its been mentioned that biomarkers indicate the presence of biological substance of the past or present. The argument assumes that it is of the past. D offers evidence otherwise

Posted from my mobile device

Basshead · Answer

To weaken the geologist's argument, we can either  attack the geologist's reasoning  or  provide evidence that deep carbon is the source of petroleum (strengthening the scientists' view) .

Let's break this argument down:

The   dominant view   is that petroleum formed from the fossilized remains of plants and animals deep in the earth's crust.

Scientists have   challenged   this dominant view, claiming that petroleum actually formed   from deep carbon deposits dating from the formation of the earth.

The geologist   disagrees   with the scientists, reasoning that their theory is refuted by the presence in petroleum of biomarkers.

The geologist believes that the presence in petroleum of biomarkers refutes the scientists' views.

Choice D tells us that certain strains of bacteria thrive deep inside the earth's crust. This weakens the geologist's view -- that the biomarkers signify past or present existence of living organisms. Perhaps the petroleum caught some of the strains of bacteria that thrive in the earth's crust. If so, it's possible the petroleum formed from deep carbon (scientist's view).

Choice D is the answer.

VerbalBot · Answer

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Geologist: The dominant view that petroleum formed from the fossilized

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Geologist: The dominant view that petroleum formed from the fossilized

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