LSAT 142 – Section 1 – Question 23

LSAT 142 - Section 1 - Question 23

December 2014

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT142 S1 Q23
+LR
Weaken +Weak
Causal Reasoning +CausR
Eliminating Options +ElimOpt
A
24%
161
B
13%
161
C
5%
158
D
39%
167
E
19%
164
158
169
180
 +Hardest 145.991 +SubsectionMedium

J.Y.’s explanation

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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.

Summarize Argument: Phenomenon-Hypothesis
The author concludes that petroleum did not form from deep carbon deposits dating from the formation of the earth. This is based on the fact that petroleum contains biomarkers, which indicate the past or present existence of a living organism.

Notable Assumptions
The author assumes that if petroleum formed from deep carbon deposits, then we would not find biomarkers in it. This overlooks the fact that there might be reasons that biomarkers could be found in petroleum, even if the petroleum formed from deep carbon deposits (as opposed to forming from living things).

A
Fossils have been discovered that are devoid of biomarkers.
Presence of biomarkers indicate past/present life. But that doesn’t mean no biomarkers indicates no past/present life. This doesn’t suggest fossils aren’t connected to life. Also, (A) just means some fossils don’t have biomarkers; the vast majority could have them.
B
Living organisms only emerged long after the earth’s formation.
Petroleum could have formed after those living organisms emerged. The stimulus never suggested petroleum dates to the formation of the earth. It could have come about billions of years afterward.
C
It would take many millions of years for organisms to become petroleum.
Petroleum could have formed many millions of years after organisms emerged. The stimulus doesn’t suggest petroleum dates to the formation of earth. It could have come about billions of years afterward.
D
Certain strains of bacteria thrive deep inside the earth’s crust.
This shows how petroleum might come to contain biomarkers even if it formed from deep carbon deposits. Some bacteria, which is a living organism, could be the origin of the biomarkers. This bacteria is “deep inside the earth’s crust,” which is where “deep” carbon deposits exist.
E
Some carbon deposits were formed from the fossilized remains of plants.
The scientists think petroleum formed from “deep carbon deposits dating from the formation of the earth.” There may be other deep carbon deposits that came after life, such as what (E) describes, but those are different deposits unrelated to the scientists’ view.

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LSAT PrepTest 142 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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