LSAT 143 – Section 4 – Question 08

LSAT 143 - Section 4 - Question 08

June 2015

You need a full course to see this video. Enroll now and get started in less than a minute.

Request new explanation

Target time: 1:25

This is question data from the 7Sage LSAT Scorer. You can score your LSATs, track your results, and analyze your performance with pretty charts and vital statistics - all with a Free Account ← sign up in less than 10 seconds

Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT143 S4 Q08
+LR
+Exp
Weaken +Weak
Causal Reasoning +CausR
A
2%
153
B
2%
156
C
7%
154
D
2%
155
E
87%
165
139
147
154
 +Medium 146.108 +SubsectionMedium

The giant Chicxulub crater in Mexico provides indisputable evidence that a huge asteroid, about six miles across, struck Earth around the time many of the last dinosaur species were becoming extinct. But this catastrophe was probably not responsible for most of these extinctions. Any major asteroid strike kills many organisms in or near the region of the impact, but there is little evidence that such a strike could have a worldwide effect. Indeed, some craters even larger than the Chicxulub crater were made during times in Earth’s history when there were no known extinctions.

Summarize Argument
The author concludes that an asteroid strike wasn’t responsible for most dinosaurs going extinct. This is because a major asteroid strike doesn’t have worldwide consequences, and even bigger asteroids than the one that supposedly caused the dinosaurs to go extinct have been accompanied by no known extinctions whatsoever.

Notable Assumptions
In order for the asteroid strike not to have caused most dinosaur extinctions, the author must believe that most dinosaurs weren’t located in the region that the asteroid struck. The author must also believe that climactic conditions at the time—i.e. drought—didn’t intensify the strike’s effects, perhaps by releasing significantly more dust than usual into the Earth’s atmosphere and blocking out the sun.

A
The vast majority of dinosaur species are known to have gone extinct well before the time of the asteroid impact that produced the Chicxulub crater.
The author likely agrees. The dinosaurs in question are just the “last dinosaur species.”
B
The size of a crater caused by an asteroid striking Earth generally depends on both the size of that asteroid and the force of its impact.
We don’t really care about the crater. We already know asteroids leaving larger craters caused no known extinctions.
C
Fossils have been discovered of a number of dinosaurs that clearly died as a result of the asteroid impact that produced the Chicxulub crater.
The author agrees that some dinosaurs died, but qualifies that the effects of the asteroid were regional. We need to weaken the claim that the asteroid couldn’t have caused widespread dinosaur extinctions.
D
There is no evidence that any other asteroid of equal size struck Earth at the same time as the asteroid that produced the Chicxulub crater.
The author never claimed there were two asteroids.
E
During the period immediately before the asteroid that produced the Chicxulub crater struck, most of the world’s dinosaurs lived in or near the region of the asteroid’s impending impact.
While the asteroid only had a regional effect, most dinosaurs lived in that region. Thus, the asteroid caused most dinosaur extinctions.

Take PrepTest

Review Results

LSAT PrepTest 143 Explanations

Section 1 - Logical Reasoning

Section 2 - Reading Comprehension

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

Get full LSAT course

Leave a Reply