LSAT Explanation PT 25, S2, Q10: Insects can see ultraviolet light and

LSAT Question Stem

Which one of the following, if true, most strongly supports the argument? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The argument consists of the following premises and conclusion:

Premise 1: Insects can see ultraviolet light.

Premise 2: Insects identify important food sources and mating sites by sensing the characteristic patterns of ultraviolet light that these things reflect.

Premise 3: Insects are attracted to Glomosus spiderwebs, which reflect ultraviolet light.

Conclusion: Insects are probably attracted to Glomosus spiderwebs because of the specific patterns of ultraviolet light that these webs reflect.

The argument is structured as a causal explanation, suggesting that the specific patterns of ultraviolet light reflected by Glomosus spiderwebs are the probable cause for insects' attraction to these webs. The question we need to answer is a Strengthen question, which asks us to find the answer choice that most strongly supports the argument.

Now, let's discuss the answer choices:

a) This answer choice tells us about other spider webs that do not reflect ultraviolet light when illuminated with white light containing an ultraviolet component. However, this information does not help strengthen the argument about Glomosus spiderwebs and their specific patterns of ultraviolet light attracting insects. It's not relevant to the argument, so it's not the correct answer.

b) This answer choice talks about the silks of spiders used for lining burrows and covering eggs, which also reflect ultraviolet light. However, this information does not directly support the argument about Glomosus spiderwebs and their specific patterns of ultraviolet light attracting insects. It's not relevant to the argument, so it's not the correct answer.

c) This answer choice discusses the common garden spider and its webs reflecting ultraviolet light in certain portions. While it provides information about another type of spiderweb reflecting ultraviolet light, it does not directly support the argument about Glomosus spiderwebs and their specific patterns of ultraviolet light attracting insects. It's not relevant to the argument, so it's not the correct answer.

d) This answer choice presents a scenario where fruit flies were placed before a Glomosus web and a synthetic web with a similar pattern that also reflected ultraviolet light. Many of the fruit flies flew to the Glomosus web. However, this answer choice does not provide enough information to support the argument that the specific patterns of ultraviolet light in Glomosus spiderwebs are the probable cause for insects' attraction. It's not clear whether the synthetic web had the same effect on the fruit flies, and the term "many" is too vague. This answer choice does not strongly support the argument, so it's not the correct answer.

e) This answer choice presents a scenario where fruit flies were placed before two Glomosus webs, one illuminated with white light containing an ultraviolet component and one without. The majority of the fruit flies flew to the ultraviolet reflecting web. This answer choice isolates the ultraviolet light as a factor in the attraction of insects to the webs and directly supports the argument that the specific patterns of ultraviolet light in Glomosus spiderwebs are the probable cause for insects' attraction. This answer choice strengthens the argument and is the correct answer.

In conclusion, the correct answer to this Strengthen question is answer choice E, as it provides evidence that supports the argument that the specific patterns of ultraviolet light in Glomosus spiderwebs are the probable cause for insects' attraction.