LSAT Question Stem

Which one of the following, if true, most helps to resolve the apparent discrepancy described above? 

Logical Reasoning Question Type

This is a Paradox question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

Let's first break down the information in the passage. The passage states that kidney stones can form when urine is overly concentrated with calcium or oxalate. It was believed that reducing dietary calcium would decrease the likelihood of calcium concentrating and forming additional stones. However, for many people, increasing calcium intake actually decreases the chances of recurrence. This is the apparent discrepancy that we need to resolve.

Think of it this way: Imagine a glass of water with salt. If there is too much salt in the water, salt crystals start to form. One might think that reducing the amount of salt added to the water would prevent more crystals from forming. But in this case, adding more salt actually prevents new crystals from forming. This is the paradox we need to solve.

The question type is Paradox, which means we need to find an answer choice that helps resolve the apparent discrepancy described in the passage.

a) This answer choice tells us that animals with kidney stones rarely get additional stones once calcium supplements are added to their diet. While it supports the paradox, it does not explain why increasing calcium intake decreases the chances of recurrence in humans. We need an explanation that applies to humans, not just animals.

b) This answer choice states that increasing dietary oxalate while reducing dietary calcium does not reduce the chances of kidney stone recurrence. This information is not relevant to our paradox, as we are trying to understand why increasing calcium intake decreases the chances of recurrence.

c) This answer choice tells us that kidney stone development can be the result of an inherited disorder that leads to excessive production of calcium and oxalate. However, it does not explain why increasing calcium intake would decrease the chances of recurrence for many people.

d) This is the correct answer. It explains that increasing calcium intake increases the amount of calcium eliminated through the intestines, which in turn decreases the amount to be filtered by the kidneys. This helps resolve the paradox because it shows that by increasing calcium intake, we are actually reducing the amount of calcium that the kidneys need to process, thus decreasing the chances of kidney stone recurrence.

e) This answer choice states that some kidney stones are composed of uric acid rather than a combination of calcium and oxalate. While this information may be true, it does not help resolve the paradox of why increasing calcium intake decreases the chances of kidney stone recurrence for many people.