Q23 - The dominant view that petroleum formed

[mshinners]

Question Type:
Weaken

Stimulus Breakdown:
Current view: Oil (petroleum) formed from dead plants/animals.
New view: Oil formed from carbon deposits.

Author premise: Biomarkers are indicators of living organisms. Oil has biomarkers.
Author conclusion: Biomarkers in oil disproves the new view.

Answer Anticipation:
The current/new view are great background, but I'd mainly focus on the new view, since it's the one the author specifically talks about. In her argument, the author uses biomarkers to disprove the new view. As I head into the answers, I'll be on the lookout for anything that suggests the presence of biomarkers argues against the carbon deposit theory. Here's where the current view would be helpful - it might argue against the carbon theory by giving evidence for the living animal view, especially in light of the discussion of biomarkers.

One final note I'd have going into the answers - the author's premise specifically talks about a timeline - "past or present existence". Another potential answer choice will deal with this detail - the biomarkers are from something more recent than when the oil was formed.

Correct answer:
(D)

Answer choice analysis:
(A) Out of scope. If anything, this answer choice weakens the argument about fossils being the source of oil. If you conflated the author's viewpoint with the dominant view, you might have picked this answer. However, the author's conclusion is just about the new theory, which doesn't mean she necessarily agrees with the old one.

(B) Out of scope. If this answer stated something about them emerging only after the formation of oil, it'd be relevant. However, we don't know the relative of oil vs. the earth.

(C) Out of scope. There have been many millions of years for oil to form, so this doesn't cut against either of the theories discussed. The answer would need to discuss the age of earth, oil, and life in order for it to be relevant.

(D) Bingo. This would most likely be a pick after eliminating the others. However, it plays off of the past/present existence line from the stimulus. This answer, by using the present tense, tells us these bacteria still exist. If the biomarkers found in oil come from bacteria that's alive today, the biomarkers would not be an indicator of the source of the oil, and so the author's contention that they are proof against the new theory would be weakened.

As an analogy, let's say we were excavating an ancient Roman site, and someone found an iPhone. They might conclude that the presence of the iPhone proves the ancient Romans were very technologically advanced. You could weaken that by saying, "Oh, that's mine - must have dropped it yesterday."

(E) Out of scope. The carbon deposits being discussed date from the formation of the earth, at which point plants could not have existed.

Takeaway/Pattern:
When the LSAT mentions any timeline, it's fair play for the answer choices. Here, mentioning "past or present" should have set off alarms in your brain!

#officialexplanation

[mist4bison]

So, I got this wrong and am still a little confused, but I' try to take a shot at it...

Argument: Some scientists say petroleum didn't form from fossilized remains, but instead from deep carbon deposits dating from the formation of the earth. These scientists are wrong, because of biomarkers found in petroleum, which indicate the past and present existence of a living organism.

So, we're looking for something that either (1) strengthens that petroleum formed from carbon deposits or (2) weakens that the biomarkers in petroleum are relevant.

(A) No bearing. We're not worried about the biomarkers in fossils; we're worried about biomarkers in petroleum.

(B) No bearing. The argument doesn't say that petroleum formed from fossils of living organisms dating from the Earth's formation. The carbon deposit argument mentions this, not the fossil argument.

(C) No bearing. Again, the geologist doesn't mention a time frame. We have no indication of when petroleum supposedly developed.

(D) Sort of weakens. If the petroleum that formed in the crust was surrounded by bacteria, maybe it's those bacteria that caused the biomarkers to form in petroleum. Keep it.

(E) Strengthen. If fossils formed carbon deposits and carbon deposits formed petroleum, then fossils did indirectly hep to form petroleum, making the geologist, although misleading, still correct.

After eliminating the other ACs, (D) is left. I'm not a huge fan of the answer, but it's certainly the least wrong.

[maryadkins]

Yep. You got it. And your process here was right. You eliminated wrong answer choices to get to the right one. (D) can be a little tricky to reach, but by eliminating the others we see that it is the best weakener.

[yding817]

Hi, thanks for your posts. I still confused why A is wrong. Please clarify further if you do not mind.

To identify the core argument, I noticed the passage has lots of distractions. But essentialy it is a pseudo-causation argument.

Core argument:
Becasue of the presense of biomarkers in petrolem, which indicates the existence of living organism, the dorminat view that petroleum formed from the fossilized remains of plants and animals is correct.

To me, A weakens the argument in this way. If fossil has no biomarker, the biomarker the author used as evidence to support the theory the it was the fossil of plants of animals made petroleum would have nothing to do with petroleum. A weakens the argument at least by suggesting the biomaker discovered is irrelent or least relevent to fossil of plants or animal.

Please correct me.

Another more general problem is , I wonder whether it is ture that more recent PTs has became weird especially to weaken/strengthen question. Ususally, there were only 1 correct answer choice in weaken/strengthen, but PT 70+ appear to provide multiple correct answer choice and require us to pick the real MOST powerful one. (Just personal observation)


Thanks in advance.

[Olivia James]

Hello -

I am not a Manhattan Prep tutor, but I was reading this post and thought that I could perhaps provide you with my thoughts until one of the tutors does respond to your questions.

1. I believe the answer to your question (if I have understood it correctly) relies on a slight error in your reading of the answer choice A - "Fossils have been discovered that are devoid of biomarkers" does NOT equal to (as you phrased it) "If Fossils have no biomarkers..."
Whereas the answer choice A simply states that SOME fossils do not contain biomarkers, you have assumed that All fossils contain no biomarkers or No fossils contain biomarkers.
Thus if you interpret A as LSAC would want you to - Saying that some fossils do not contain biomarkers is not strong enough to weaken the argument that those biomarkers in the petroleum did not stem from fossils. Perhaps there are one million fossils that do contain biomarkers and two that are devoid of biomarkers. How much would the fact that there exist two fossils that do not contain any biomarkers weaken the claim that those biomarkers that are present in the petroleum do not stem from one of the million fossils that actually do contain biomarkers? It practically has no bearing on the argument.

In general, in most (but not all) strengthener/weakener questions I would be weary of answer choices that start with some. They are usually not strong enough to impact the argument.

2. I do agree that the tests starting 70 and up have become more difficult. And the S/W questions have definitely become more tricky. I do not feel as confident with my chosen answer choice as I used to be in the older tests.

Hope that I was of some help-

Good Luck!

[cacrv]

So, I got this wrong and am still a little confused, but I' try to take a shot at it...

Argument: Some scientists say petroleum didn't form from fossilized remains, but instead from deep carbon deposits dating from the formation of the earth. These scientists are wrong, because of biomarkers found in petroleum, which indicate the past and present existence of a living organism.

So, we're looking for something that either (1) strengthens that petroleum formed from carbon deposits or (2) weakens that the biomarkers in petroleum are relevant.

(A) No bearing. We're not worried about the biomarkers in fossils; we're worried about biomarkers in petroleum.

(B) No bearing. The argument doesn't say that petroleum formed from fossils of living organisms dating from the Earth's formation. The carbon deposit argument mentions this, not the fossil argument.

(C) No bearing. Again, the geologist doesn't mention a time frame. We have no indication of when petroleum supposedly developed.

(D) Sort of weakens. If the petroleum that formed in the crust was surrounded by bacteria, maybe it's those bacteria that caused the biomarkers to form in petroleum. Keep it.

(E) Strengthen. If fossils formed carbon deposits and carbon deposits formed petroleum, then fossils did indirectly hep to form petroleum, making the geologist, although misleading, still correct.

After eliminating the other ACs, (D) is left. I'm not a huge fan of the answer, but it's certainly the least wrong.

Would someone weigh in on E? so if one unit of petroleum ("some") was formed from plant fossils (out of say, 100 units available), and thus, only 1% of petroleum in the world contain biomarkers, it can't really be used to refute the dominant view, no? thus weakening the geologist's refutation?

I was also thrown off by D because "deep inside the earth's crust" is directly related to the fossils in the stim, and it wasn't ever clarified where the deep carbon deposits lie (although I guess this could be a safe assumption that we could be allowed to make on the test that the carbon deposits lie below the fossils). So reading D, I was inclined to picture that these strains of bacteria live in the same layer of the fossils.

I'd appreciate any clarifications on my confusion over D & E!!

[haeeunjee]

I was also thrown off by D because "deep inside the earth's crust" is directly related to the fossils in the stim, and it wasn't ever clarified where the deep carbon deposits lie (although I guess this could be a safe assumption that we could be allowed to make on the test that the carbon deposits lie below the fossils). So reading D, I was inclined to picture that these strains of bacteria live in the same layer of the fossils.

I'd appreciate any clarifications on my confusion over D & E!!

Yes, exactly, the bacteria are from the earth's crust.

1- Dominant view: Earth's crust, here petroleum is formed from the fossilized remains.

2- There are researchers who push against that and say that petroleum is actually from deep carbon deposits.

3- The geologist's conclusion is that these researchers are wrong because petroleum contains biomarkers. So they're probably from fossil remains (the assumption being that fossil remains contain biomarkers).

(D) is saying: Hold up. Those biomarkers could be molecules from the strains of bacteria that live in the earth's crust, and if they are, they may NOT from fossil remains. This weakens the geologist's argument.

[SaulB691]

Atticus Finch, in your explanation for why A is wrong, you said "this actually weakens the geologist's viewpoint" but that is in fact what the question asked us to do, correct? I figured A was wrong because we could always say, perhaps some external factor in other fossils caused the biomarker to be erased, but that doesn't mean that the biomarkers present in petroleum are not indicative of past plant/animal remains.

^^ Ah I am editing this post, I now see that you addressed this..that the Geologist doesn't necessarily agree with the dominant. Good catch, thank you for that insight, I missed it!

[obobob]

Just a quick one--

can someone confirm if (D) is just saying:
there is at least one type of bacteria strain that inhabits today deep inside the earth's crust?

[ohthatpatrick]

Yes, it's saying that.

I think "certain strains" allows you believe that there is more than one strain of bacteria that presently thrive deep inside the crust.

[andreperez7]

I want to point out a way of thinking about this problem that differs from the above. Though, I certainly agree with all the great analysis above.

Conclusion: Petroleum is made of plants and animals.

Premise: Biomarkers in petroleum indicate the existence of "living organisms"

Assumption: Living Organisms --> Plants & Animals.

Question Type: Weakener

D) Correct: Weakens because it shows living organisms that biomarkers indicate could be bacteria instead of plants and animals. Both are living organisms.

I very much like mshinners' past vs. present analysis of the wording of D too.