LSAT Explanation PT 25, S2, Q15: Some plants have extremely sensitive biological

LSAT Question Stem

Which one of the following, if true, most seriously undermines the reasoning above? 

Logical Reasoning Question Type

This is a Weaken question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. The passage discusses the sensitivity of some plants to temperature changes, specifically mentioning rhododendrons and crocuses. It states that rhododendron leaves curl when the temperature is below 0°C, and mature crocus blossoms open when the temperature is above 2°C. The conclusion is that if someone observed rhododendrons with uncurled leaves, crocuses with mature but unopened blossoms, and a thermometer showing 1°C, they could determine that the thermometer's reading was accurate to within plus or minus 1°C.

The question type is Weaken, which means we are looking for an answer choice that undermines the conclusion of the argument.

Now, let's evaluate the answer choices:

a) This answer choice talks about the blooming period of rhododendrons and crocuses, but it does not address the accuracy of the thermometer's reading based on the plants' reactions to temperature. Therefore, it does not weaken the conclusion.

b) This answer choice is irrelevant to the argument. People's preferences for being outdoors at certain temperatures do not affect the accuracy of the thermometer's reading.

c) This answer choice states that the climate and soil conditions that favor the growth of rhododendrons are also favorable to the growth of crocuses. However, it does not address the accuracy of the thermometer's reading based on the plants' reactions to temperature, so it does not weaken the conclusion.

d) This is the correct answer. It states that the air temperature surrounding rhododendrons and crocuses can differ by more than 2°C, even if they are growing side by side. This undermines the conclusion that observing these plants can accurately determine the thermometer's reading, as the temperature difference between the plants could be greater than the range of 0-2°C.

e) This answer choice discusses the accuracy of certain types of thermometers in different temperature ranges. However, the argument is focused on determining the accuracy of a thermometer based on the plants' reactions to temperature. Even if certain thermometers are less accurate in warmer or colder temperature ranges, it does not directly undermine the conclusion that observing the plants can determine the thermometer's reading within a specific range.

In summary, answer choice D is the correct answer because it undermines the conclusion that observing the plants can accurately determine the thermometer's reading within a specific range. The other answer choices do not directly address the accuracy of the thermometer's reading based on the plants' reactions to temperature, so they do not weaken the conclusion.