LSAT 117 – Section 3 – Question 15

LSAT 117 - Section 3 - Question 15

October 2004

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT117 S3 Q15
+LR
+Exp
Argument part +AP
Causal Reasoning +CausR
A
0%
154
B
19%
161
C
70%
168
D
0%
157
E
11%
162
146
157
167
 +Harder 146.848 +SubsectionMedium

Seemingly inconsequential changes in sea temperature due to global warming eventually result in declines in fish and seabird populations. A rise of just two degrees prevents the vertical mixing of seawater from different strata. This restricts the availability of upwelling nutrients to phytoplankton. Since zooplankton, which feed upon phytoplankton, feed the rest of the food chain, the declines are inevitable.

Summarize Argument: Phenomenon-Hypothesis
The author concludes that changes in sea temperature that seem small will result in declining fish and seabird populations. This conclusion is supported by a description of a causal chain: a temperature increase of two degrees prevents the vertical mixing of seawater, which prevents phytoplankton from having access to nutrients. Zooplankton consume phytoplankton, so these zooplankton lose their food source, and the rest of the food chain is based on zooplankton. So the seemingly minor temperature increase results in a loss in food for the entire food chain.

Identify Argument Part
The statement in the question stem demonstrates how the loss of nutrients for phytoplankton impacts food sources for the broader food chain. (Zooplankton consume phytoplankton, and everything else relies on zooplankton for nutrients).

A
It is a hypothesis supported by the fact that phytoplankton feed on upwelling nutrients.
The fact that zooplankton consume phytoplankton does not receive support from any other part of the argument; it is a premise that we accept at face value. Further, it is not a hypothesis; it is a premise that supports the conclusion.
B
It is intended to provide an example of the ways in which the vertical mixing of seawater affects feeding habits.
The claim in the question stem is a description of a general relationship that is used as a premise. Also, it is not about the impact on feeding habits; it is about food access. The zooplankton would still eat phytoplankton if they were available.
C
It helps show how global temperature changes affect larger sea animals indirectly.
The statement in the question stem connects zooplankton to phytoplankton. This connection is a link in the causal chain that more broadly connects temperature increases to declining populations of fish and seabirds, showing how temperature changes affect sea animal populations.
D
It is offered as one reason that global warming must be curtailed.
There is no value judgement in the argument; the argument does not give any recommendations for action.
E
It is offered in support of the idea that global warming poses a threat to all organisms.
This argument shows how global warming poses a threat to fish and seabird populations, not to all organisms generally. This answer choice is too broad.

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LSAT PrepTest 117 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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