LSAT 155 – Section 4 – Question 10

LSAT 155 - Section 4 - Question 10

November 2019

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT155 S4 Q10
+LR
Strengthen +Streng
Causal Reasoning +CausR
Analogy +An
A
4%
151
B
85%
161
C
4%
150
D
6%
154
E
1%
150
133
142
151
 +Medium 147.589 +SubsectionMedium

Many species of plants produce nectars known as extrafloral nectories (EFNs), which are known to attract certain ants that defend the plants against leaf-eating insects. Recently, greenhouse experiments have found that jumping spiders jump onto plants with active EFNs six times more often than they jump onto plants without EFNs, and regularly eat the nectar. So, like the ants, jumping spiders apparently defend EFN-producing plants against leaf-eating insects.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that jumping spiders defend EFN-producing plants against leaf-eating insects. He supports this by noting that ants that display behavior similar to that of the spiders defend the plants. He then cites experiments showing that the spiders land on plants with active EFNs six times more often than on those without EFNs, and they regularly eat the plant's nectar.

Notable Assumptions
The author assumes that there’s no alternative explanation for the spiders’ attraction to the EFN-producing plants, simply because the spiders’ behavior is similar to the ants’ behavior. He implicitly rules out all other explanations. But maybe the spiders just land on the plants for food and have a neutral or even negative effect on the plants’ health.

A
For many species of nectar-producing plants, productivity is increased when a plant is protected from leaf-eating insects.
Irrelevant—this doesn’t rule out any alternative explanations for the spiders’ behavior. It makes sense that plants are more productive when protected from leaf-eating insects, but (A) doesn’t address whether the spiders themselves are actually protecting the plants.
B
In field experiments, the introduction of jumping spiders into an environment was followed by a significant increase in the population of EFN-producing plants.
This strengthens the author’s hypothesis by validating a prediction that would follow from it. If his hypothesis were true, we’d expect to see the plants thriving and reproducing when the spiders are introduced, since the spiders protect them from leaf-eating insects.
C
Some species of EFN-producing plants cannot survive without some outside agent protecting them from leaf-eating insects.
Irrelevant— this fails to address whether jumping spiders are protecting the plants from leaf-eating insects and thus fails to strengthen the argument.
D
Experiments with types of spiders other than jumping spiders suggest that these other types of spiders do not defend EFN-producing plants.
Irrelevant— the argument is only concerned with whether or not the jumping spiders defend EFN-producing plants. The effect of other types of spiders on EFN-producing plants doesn’t matter.
E
Regions with large populations of ants also tend to have large populations of EFN-producing plants.
Irrelevant— we already know that certain ants protect EFN-producing plants from leaf-eating insects, so it makes sense that areas with lots of ants also have lots of EFN-producing plants. But (E) fails to address whether jumping spiders also protect these plants.

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LSAT PrepTest 155 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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