LSAT Explanation PT 43, S2, Q7: Failure to rotate crops depletes the

LSAT Question Stem

Suppose there were some vegetables that were grown in soil to which fertilizer had never been applied. On the basis of the passage, which one of the following would have to be true regarding those vegetables? 

Logical Reasoning Question Type

This is a Must Be True question. 

Correct Answer

The correct answer to this question is C. 

LSAT Question Complete Explanation

This LSAT problem presents a passage discussing the effects of crop rotation, soil nutrient depletion, and the use of fertilizers and pesticides on vegetable growth and human health. Let's break down the passage step by step before diving into the question and answer choices.

1. Failure to rotate crops depletes the soil's nutrients gradually unless other preventive measures are taken.

- This tells us that not rotating crops (NRC) leads to soil nutrient depletion (D) unless there are preventive measures (PM).

- Diagram: NRC -> D / PM

- Contrapositive: /D -> RC or PM

2. If the soil's nutrients are completely depleted, additional crops cannot be grown unless fertilizer is applied to the soil.

- This tells us that if the soil is completely depleted (CD), additional crops (AC) can't grow without fertilizer (F).

- Diagram: CD -> /AC / F

- Contrapositive: AC -> /CD or F

3. Vegetables grown in fertilized soil are more vulnerable to pests and require more pesticides, which increases health risks to humans.

- This statement doesn't need a diagram, but it's important to remember that fertilized soil leads to more pesticides and greater health risks.

Now, let's analyze the question: Suppose there were some vegetables that were grown in soil to which fertilizer had never been applied. On the basis of the passage, which one of the following would have to be true regarding those vegetables?

The question type is Must Be True (MBT). We need to find a statement that must be true based on the passage's information.

Answer Choices:

a) The soil in which the vegetables were grown may have been completely depleted of nutrients because of an earlier failure to rotate crops.

- This answer choice is incorrect because we know that if the soil was completely depleted, the vegetables could not grow without fertilizer. Since the vegetables grew without fertilizer, the soil could not have been completely depleted of nutrients.

b) It is not possible that the vegetables were grown in soil in which crops had been rotated.

- This answer choice is incorrect because it is very much possible that these vegetables grew in soil in which crops had been rotated. The passage tells us that either the crops were rotated or other preventative measures were taken when the soil's nutrients are not completely depleted.

c) The vegetables were grown in soil that had not been completely depleted of nutrients but not necessarily soil in which crops had been rotated.

- This is the correct answer choice. The vegetables grew without fertilizer, so the soil could not have been completely depleted of nutrients. However, the crops do not have to be rotated (it is not necessary) as long as other preventative measures were taken.

d) Whatever the health risks to humans from eating the vegetables, these risks would not be attributable to the use of pesticides on them.

- This answer choice is incorrect because it cannot be clearly known whether pesticides are the actual cause of health risks to humans who eat the vegetables. The passage states that the more pesticides used on vegetables, the greater the health risks to humans, which goes against this answer choice.

e) The health risks to humans from eating the vegetables were no less than the health risks to humans from eating the same kinds of vegetables treated with pesticides.

- This answer choice is incorrect because it contradicts the passage's statement that the more pesticides used on vegetables, the greater the health risks to humans. Thus, vegetables treated with pesticides would pose a greater risk than vegetables that were not treated with pesticides.

So, the correct answer is (C): The vegetables were grown in soil that had not been completely depleted of nutrients but not necessarily soil in which crops had been rotated.