Generally speaking, if the same crop is sown in a field for several successive years, growth in the later years is poorer than growth in the earlier years, since nitrogen in the soil becomes depleted. Even though alfalfa is a nitrogen-fixing plant and thus increases the amount of nitrogen in the soil, surprisingly, it too, if planted in the same field year after year, grows less well in the later years than it does in the earlier years.

"Surprising" Phenomenon
Alfalfa increases the nitrogen in the soil, yet it struggles when planted in the same field year after year.

Objective
A hypothesis explaining this similarity must imply that alfalfa will struggle when planted in successive years. This may be a consequence of increased nitrogen in the soil, or it may be unrelated to nitrogen.

A
Some kinds of plants grow more rapidly and are more productive when they are grown among other kinds of plants rather than being grown only among plants of their own kind.
It is not stated whether alfalfa is one such plant, nor is it stated whether alfalfa is typically mixed with other crops. This does not address the success of crops that are planted in the same field in successive years.
B
Alfalfa increases the amount of nitrogen in the soil by taking nitrogen from the air and releasing it in a form that is usable by most kinds of plants.
This simply describes the mechanism by which alfalfa increases nitrogen in the soil. It does not explain why alfalfa struggles when planted in successive years.
C
Certain types of plants, including alfalfa, produce substances that accumulate in the soil and that are toxic to the plants that produce those substances.
This explains why alfalfa struggles when planted in successive years. Though the soil accumulates nitrogen, it also accumulates toxic substances that are detrimental to alfalfa’s health.
D
Alfalfa increases nitrogen in the soil in which it grows only if a certain type of soil bacteria is present in the soil.
This does not state whether the required bacteria exists in alfalfa fields. It establishes a condition necessary for alfalfa to be nitrogen-fixing but takes no position on whether that condition is satisfied.
E
Alfalfa is very sensitive to juglone, a compound that is exuded from the leaves of black walnut trees.
This information is useless without more context. No given information suggests that black walnut leaves will more likely be present in fields where alfalfa is grown in successive years.

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Hospital auditor: The Rodríguez family stipulated that the funds they donated to the neurological clinic all be used to minimize patients’ suffering. The clinic administration is clearly violating those terms, since it has allocated nearly one fifth of those funds for research into new diagnostic technologies, instead of letting that money flow directly to its patients.

Clinic administrator: But the successful development of new technologies will allow early diagnosis of many neurological disorders. In most cases, patients who are treated in the early stages of neurological disorders suffer far less than do patients who are not treated until their neurological disorders reach advanced stages.

Speaker 1 Summary
The hospital auditor argues that the clinic is not using all of the donated funds to minimize patients’ suffering, contrary to the terms of the donation. Why not? The clinic is using a portion of the money to research new diagnostic technology. The auditor presumably believes that this does not help to minimize suffering.

Speaker 2 Summary
The clinic administrator leads us to the implied conclusion that these research funds are helping to minimize suffering. How so? Because new technologies will allow early diagnosis of some disorders, and patients who are treated early usually suffer much less than patients who are treated later.

Objective
We’re looking for a disagreement between the speakers. They disagree about whether the clinic’s use of donated funds is meeting the requirement to minimize suffering.

A
whether early treatment of many neurological disorders lessens the suffering associated with those disorders rather than completely eliminating such suffering
Neither speaker discusses this claim. Even the clinic administrator, who talks about early treatment reducing suffering, never specifies whether the reduction is partial or whether it can eliminate suffering.
B
whether the patients being treated at the neurological clinic are currently receiving adequate treatment for the neurological disorders from which they suffer
Neither speaker talks about this point. The auditor and administrator are arguing about the use of donated funds, not about the actual quality of care patients are currently receiving.
C
whether the Rodríguez family clearly stipulated that the funds they donated to the neurological clinic be used to minimize patients’ suffering
The hospital auditor agrees that this is the case, but the clinic administrator never disagrees. The administrator doesn’t directly say anything about the terms of the donation.
D
whether the neurological clinic is adhering strictly to the conditions the Rodríguez family placed on the allocation of the funds they donated to the clinic
The auditor thinks that this is not true, while the administrator thinks that it is: this is the disagreement. The auditor explicitly states that the clinic is violating the conditions. The administrator, though, explains how the clinic is actually using the money as required.
E
whether the Rodríguez family anticipated that some of the funds they donated to the neurological clinic would be used to pay for research into new diagnostic technologies
Neither speaker makes this claim. Neither the hospital auditor nor the clinic administrator says anything about the specific ways that the Rodríguez family expected the money to be used.

8 comments