Geologist: The dominant view that petroleum formed from the fossilized

Hi,

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

Regards

broall can you explain this one ? :/

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

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 ?

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.

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

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).

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

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: “[petroleum] 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!

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?

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.

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

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.

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.