Summary
Antibiotics in animal feed keep animals healthy and increase meat yields. However, scientists recommend reducing antibiotics in animal feed because they believe it may cause antibiotics to be less effective for humans. If meat yields are reduced, some farmers will go out of business.
Strongly Supported Conclusions
If no other method of increasing meat yields is employed, then some farmers will go out of business if antibiotics in animal feed are reduced.
A
If scientists are correct that antibiotic use in animal feed makes antibiotics less effective in humans, then some farmers will go out of business.
This answer is unsupported. We don’t know from the stimulus what condition would be triggered if the scientists’ hypothesis is correct. The scientists could be correct and no action is taken.
B
If antibiotic use in animal feed is not phased out, some antibiotics will become ineffective in humans.
This answer is unsupported. The scientists hypothesize that antibiotics in animal feed make antibiotics less effective in humans. Saying the antibiotics would become “ineffective” is too strong.
C
If the scientists’ recommendation is not heeded, no farmers will go out of business due to reduced meat yields.
This answer is unsupported. There could be other factors that cause farmers to go out of business.
D
If the health of their animals declines, most farmers will not be able to stay in business.
This answer is unsupported. “Most” farmers is too strong in this answer. We don’t know from the stimulus whether most farmers are animal farmers.
E
If antibiotic use in animal feed is phased out, some farmers will go out of business unless they use other means of increasing meat yields.
This answer is strongly supported. Reduced meat yields is a sufficient condition for farmers going out of business. So, unless there’s another way of increasing meat yields, some farmers will go out of business if meat yields are reduced by phasing out antibiotics.
Summarize Argument
The author concludes that Sarah uses the pool at City Gym. This is based on the fact that in order to use the pool at the gym, one must have a membership, and Sarah has a membership.
Identify and Describe Flaw
The author confuses a necessary condition for using the pool (having a membership) with a sufficient condition. Although Sarah meets the necessary condition because she has a membership, that doesn’t imply that she must use the pool.
A
mistakes a policy that is strictly enforced for a policy to which exceptions are made
The argument doesn’t rely on any purported exceptions to the policy that membership is required in order to use the pool.
B
treats a statement whose truth is required for the conclusion to be true as though it were a statement whose truth ensures that the conclusion is true
Sarah’s membership is required for her to use the pool. But this does not ensure that she uses the pool.
C
presumes that one or the other of two alternatives must be the case without establishing that no other alternative is possible
The argument’s reasoning doesn’t rely on presenting two alternatives.
D
concludes that a person has a certain attribute simply because that person belongs to a group most of whose members have that attribute
The argument doesn’t go from whole to part. The premise doesn’t assert that there’s a group that uses the pool.
E
draws a conclusion that merely restates a claim presented in support of that conclusion
(E) describes circular reasoning. The argument’s conclusion doesn’t restate a premise.
Matilda: The current poor condition of the university libraries is the fault of the library officials, not the students. Students should not have to pay for the mistakes of careless library administrators.
Speaker 1 Summary
Annie concludes that the university’s administrators should admit that their policies have been in error, should charge students a library fee, and should use the funds for library improvements. This is based on the fact that there have been few books purchased in the last decade, most older books are damaged, and charging students a fee is the fastest way possible to address these problems.
Speaker 2 Summary
Matilda concludes that students should not have to pay a library fee. This is because the problems with the library are the fault of library officials.
Objective
We’re looking for a disagreement. The speakers disagree about whether students should be charged a fee to improve the library.
A
library administrators are to blame for the poor condition of the university libraries
Not a point of disagreement. Annie blames university administrators, who are reasonably considered the same as the library officials Matilda blames. Even if they’re not, Annie might still blame both library officials and university administrators.
B
library improvements could be most quickly effected through charging students additional fees
Matilda expresses no opinion. She might agree with Annie that a student fee is the fastest way to improve the library.
C
students will ultimately benefit from the library improvements that could be funded by additional student fees
Matilda expresses no opinion. She doesn’t suggest any opinion about the results of student fees or of library improvements. In addition, it’s reasonable to think Matilda agrees that library improvements would help users of the library, such as students.
D
those not responsible for the current condition of the libraries should bear the cost for remedying it
This is a point of disagreement. Matilda thinks students should not be responsible for improvements. Annie believes students should be charged a fee for library improvements. She doesn’t explicitly say students aren’t responsible, but she blames administrators’ policies.
E
funds for library improvements could be raised without additional student fees
Not a point of disagreement. Matilda doesn’t discuss whether the university can get funds without a student fee.
Summary
Scientists examined diamonds formed 2.9 billion years ago and concluded these diamonds had higher-than-normal concentrations of sulfur-33. The only way this concentration occurs is from a chemical reaction triggered by ultraviolet light. If there was more than a trace of oxygen in the atmosphere 2.9 billion years ago, then not enough ultraviolet light would be present to cause the chemical reaction.
Strongly Supported Conclusions
2.9 billion years ago the atmosphere had at most very little oxygen.
A
Most diamonds with higher-than-normal concentrations of sulfur-33 were formed at least 2.9 billion years ago.
This answer is unsupported. We don’t know if this is true of most diamonds with this concentration. We only know from the stimulus that there are at least a few of them formed 2.9 billion years ago.
B
Ultraviolet light causes the oxygen in Earth’s atmosphere to react chemically with sulfur-33.
This answer is unsupported. We don’t know whether the oxygen is specifically reacting with sulfur-33. We only know from the stimulus that a “certain chemical reaction” occurs when stimulated by ultraviolet light.
C
Earth’s atmosphere contained very little, if any, oxygen 2.9 billion years ago.
This answer is strongly supported. This answer explains why the diamonds in the stimulus have higher than normal concentrations of sulfur-33.
D
Sulfur-33 is rarely found in diamonds that were formed more recently than 2.9 billion years ago.
This answer is unsupported. We don’t know anything about more recently formed diamonds from the stimulus. The stimulus is strictly limited to the diamonds scientists are examining from 2.9 billion years ago.
E
The formation of diamonds occurs only in the presence of ultraviolet light.
This answer is unsupported. We don’t know from the stimulus under what conditions diamonds are formed generally.
When a patient failed to respond to prescribed medication, the doctor hypothesized that the dosage was insufficient. The doctor first advised doubling the dosage, but the patient’s symptoms remained. It was then learned that the patient regularly drank an herbal beverage that often inhibits the medication’s effect. The doctor then advised the patient to resume the initial dosage and stop drinking the beverage. The patient complied, but still showed no change. Finally, the doctor advised the patient to double the dosage and not drink the beverage. The patient’s symptoms disappeared. Hence, the doctor’s initial hypothesis was correct.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that the doctor’s initial hypothesis—that the original dosage was too low—was correct. She supports this by describing three sets of recommendations made by the doctor:
Double the dosage. (Symptoms remained.)
Return to original dosage but stop drinking a beverage that inhibits the medication. (Symptoms remained.)
Double the dosage again, keep avoiding the beverage. (Symptoms disappeared!)
Describe Method of Reasoning
The second set of recommendations lends support to the initial hypothesis that the dosage was too by eliminating an alternative hypothesis. Since the patient’s symptoms remained after this set of recommendations, it’s likely that the beverage wasn’t the sole cause of the original dosage’s ineffectiveness.
A
They establish that the doctor’s concerns about the healthfulness of the beverage were well founded.
Actually, when the patient stopped drinking the beverage and returned to the original dosage, his symptoms still remained. So the results of the second set of recommendations don’t yet establish that the doctor’s concerns about the beverage were well founded.
B
They make it less plausible that the beverage actually contributed to the ineffectiveness of the prescribed medication.
The patient’s symptoms remained after quitting the beverage and returning to the original dosage. Even if the beverage is a contributing factor, these results suggest that the original dosage is indeed too low, whether the patient is drinking the beverage or not.
C
They give evidence that the beverage was responsible for the ineffectiveness of the prescribed medication.
We don't know yet if the beverage caused the medicine to be ineffective. In fact, because the symptoms remained, we now know that the beverage alone wasn’t entirely responsible. Also, if (C) were true, it would weaken the original hypothesis; we need an answer that supports it.
D
They suggest that the beverage was not the only cause of the ineffectiveness of the prescribed dosage.
Since the symptoms remained after stopping the beverage, it shows the beverage wasn't the only cause of the dosage's ineffectiveness. This supports the hypothesis that the dosage was too low by eliminating the alternative hypothesis that the beverage alone was responsible.
E
They rule out the possibility that the doctor had initially prescribed the wrong medication for the patient’s ailments.
The results of the second set of recommendations don’t rule out this possibility because it’s still unclear whether a higher dosage of the original medication will help the patient or not.
Summarize Argument
Contrary to the opinion of most builders, the author concludes that it’s likely papercrete is promising for large-scale construction. This is because those who regularly work with papercrete think it’s promising, and those people are familiar with the properties of the material.
Identify and Describe Flaw
The author cites to the familarity with papercrete properties among those who regularly work with papercrete. This familiarity is why the author favors their opinion over most builders. But this assumes that most builders do not have familarity with papercrete properties. If they do, then familiarity with papercrete is no longer a basis to give weight to one opinion over the other.
A
confuses what is promising for small-scale construction with what is promising for large-scale construction
The author doesn’t assume that what’s promising for small-scale must also be promising for large-scale. He relies on the opinion of those who regularly work with papercrete. Also, we don’t know that papercrete actually is promising for small-scale.
B
presumes that what the majority of builders thinks is promising must in fact be promising
Most builders don’t consider papercrete promising for large-scale construction. So the author is actually going against majority opinion.
C
equivocates between two different meanings of the term “promising”
There’s no indication “promising” means two different things in the argument. “Promising” uses the ordinary dictionary definition for this context (definition = showing signs of future success).
D
does not consider the views of the builders who have the most experience working with the material
If we assume those who use papercrete regularly have the most experience, the author does consider their views. If we don’t know whether they have the most experience, then (D) is inaccurate because we don’t know whether the author ignored the views of the most experienced.
E
fails to consider that most builders might not regularly use papercrete precisely because they are familiar with its properties
(E) points out that the builders who don’t think papercrete is promising might be familiar with papercrete’s properties. So, pointing to the familiarity of those who do think papercrete is promising is no longer a reason to rely on their opinion over the opinion of most builders.
Summary
The author concludes that none of the many interesting plays written last year will be popular several centuries from now.
Why? Because of the following:
In order for a play to be performed regularly over many decades and centuries, it must skillfully explore human nature.
The plays written last year (including the interesting ones) do not skillfully explore human nature.
Why? Because of the following:
In order for a play to be performed regularly over many decades and centuries, it must skillfully explore human nature.
The plays written last year (including the interesting ones) do not skillfully explore human nature.
Notable Assumptions
Notice that the conclusion bring up a new concept — not being popular several centuries from now. The premises don’t say anything about what will be unpopular several centuries from now, so we know the author must assume something about this concept.
To go further, we can anticipate a more specific connection to get from the premises to the conclusion. We know from the premises that the interesting plays written last year won’t be performed regularly over the coming decades and centuries (because they don’t examine human nature in a particularly skillful way). The author assumes that if the plays aren’t performed regularly over the coming decades and centuries, then they won’t be popular several centuries from now. Or, in other words, in order to be popular several centuries from now, they must be performed regularly.
To go further, we can anticipate a more specific connection to get from the premises to the conclusion. We know from the premises that the interesting plays written last year won’t be performed regularly over the coming decades and centuries (because they don’t examine human nature in a particularly skillful way). The author assumes that if the plays aren’t performed regularly over the coming decades and centuries, then they won’t be popular several centuries from now. Or, in other words, in order to be popular several centuries from now, they must be performed regularly.
A
No play will be popular several centuries from now unless it continues to be performed regularly during the intervening time.
This is the necessary link between the premises and the conclusion. If this were not true — if plays could be popular centuries from now even if they weren’t regularly performed — then the premises wouldn’t prove that the plays won’t be popular centuries from now.
B
For a play to deserve high critical acclaim it must be popular for more than just a few years.
The author’s reasoning has nothing to do with critical acclaim. The author mentioned critical acclaim in the beginning, but that was simply part of context and plays no role in the premise to conclusion structure of the author’s argument.
C
There were no plays written last year that the drama critic has neither read nor seen performed.
Not necessary, because the critic doesn’t have to have seen or read all the plays. We know as a premise that none of the plays written last year examine human nature in a skillful way. The critic doesn’t need to have seen or read all plays in order for that premise to be true.
D
If a play does not skillfully explore human nature, it will not receive critical acclaim.
The author’s reasoning has nothing to do with critical acclaim. The author mentioned critical acclaim in the beginning, but that was simply part of context and plays no role in the premise to conclusion structure of the author’s argument.
E
Any play that skillfully examines human nature will be performed regularly over the centuries.
The author’s argument concerns plays that do NOT skillfully examine human nature and what will happen to them. So the author doesn’t need to assume anything about what will happen to plays that DO skillfully examine human nature.