Summarize Argument
Dinosaurs were likely warm-blooded because the oxygen isotopes in their bones suggest that their limbs had the same body temperature as the rest of their body. And typically, the body temperature of modern cold-blooded animals much is higher than their limbs.
Notable Assumptions
The author assumes that the discrepancy in the body/limb temperature of modern cold-blooded animals was the same as cold-blooded animals during the time of the dinosaurs. The author also assumes that the process of determining body temperature from bones is applicable to dinosaur fossils.
A
Large warm-blooded animals keep their core body temperature slightly higher than the body temperature in their limbs.
This does not weaken because dinosaurs' core body and limb temperature are still much closer to the ratio of warm-blooded animals. Thus, this does not weaken the claim that dinosaurs were warm-blooded.
B
The fossilization process introduces changes to bones such that their original oxygen isotope ratios cannot be predicted.
This weakens the argument because it casts doubt on the process by which the evidence was discovered. If the fossilization process changes the oxygen distribution, then the evidence about the body temperature cannot be relied on to reach a sound conclusion.
C
Oxygen was more abundant in Earth’s atmosphere during the period in which the dinosaurs lived.
You must make several unwarranted assumptions to make this work. The fact that more oxygen was prevalent in the atmosphere does not mean dinosaur bones have more oxygen. AC B does a much better job of weakening the process of how the evidence was collected.
D
Small warm-blooded animals like mice tend to have more uniform body temperatures than do large warm-blooded animals like elephants.
This does not weaken the argument that dinosaurs are warm-blooded. This AC just compares small and large warm-blooded animals. You have to make many unwarranted assumptions for this to work.
E
Warm-blooded animals are more active and use more oxygen than cold-blooded animals.
This is irrelevant to the argument’s reasoning. This just provides a characteristic of warm-blooded animals but does not challenge the evidence or reasoning in the stimulus.
Actors generally learn their lines by focusing on the meanings of the words, the motivations of the characters uttering them, and the physical and emotional dimensions of their own performances. It seems likely that memory can be enhanced by factors such as emotion, action, and context, so this approach is probably more effective than mere rote memorization.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that actors learn lines more effectively by focusing on the meanings, motivations, and physical and emotional aspects of performance, rather than simply using rote memorization. She supports this by hypothesizing that factors like emotion, action, and context can likely improve memory.
Notable Assumptions
The author assumes that, because factors like emotion, action, and context can likely improve memory generally, they also likely improve memory in the context of learning lines. She also assumes that the actors’ approach is more effective than rote memorization without considering any potential benefits of rote memorization.
A
Test subjects are best able to remember items on a shopping list when they are also told how those items will be used.
This strengthens the argument by providing data to support the hypothesis that context improves memory. This then strengthens the conclusion that contextualization is an effective approach to learning lines.
B
The actors who are able to deliver the greatest amount of dialogue most effortlessly are those who have spent the most time learning their lines.
This does not strengthen the argument because it doesn’t address the memorization method used. We don’t know if the actors in (B) used the author’s described approach, rote memorization, or another method.
C
Actors are more readily able to remember lines learned while making an appropriate motion—for example, walking across a stage—than lines learned without an accompanying action.
This strengthens the argument because it provides an example that supports the hypothesis that emotion, action, and context can improve memory. If actors memorize better by linking lines to actions, the author’s conclusion that this is an effective approach is much stronger.
D
People who try to memorize information by imagining that they are conveying it to somebody else who needs the information show higher retention than those who try to memorize the material by rote.
This strengthens the argument by providing an example in which memorization that involves emotion, motivation, and contextualization is more effective than rote memorization.
E
People with no acting experience are able to memorize and deliver lines from a play more accurately after they have read and understood the entire play.
This strengthens the argument by showing that line-learning is enhanced by understanding the context of a play. This supports the hypothesis that context improves memory and thus also supports the conclusion that this is an effective approach to learning lines.
Summary
The stimulus can be diagrammed as follows:
Notable Valid Inferences
Temporal art forms must be experienced in a fixed order and over a fixed amount of time.
Temporal art forms are not truly visual.
Truly visual art forms are not temporal.
Truly visual art forms do not require performance
Most art forms are not truly visual.
A
Truly visual art forms do not essentially involve performance.
Must be true. As shown below, if we take the contrapositive of the conditional chain, we see that a truly visual art form does not require performance.
B
Poetry is less like music than it is like painting.
Could be false. We don’t have enough information to compare how similar these art forms are.
C
Spatiality and temporality are mutually exclusive components of art forms.
Could be false. The stimulus does not indicate that spatiality and temporality can never coexist in art.
D
Art forms that must be examined for an extended period of time in order to be understood are essentially temporal.
Could be false. (D) introduces topics that are not included in the stimulus, like understanding (rather than experiencing) art and extended (rather than fixed) periods of time.
E
Anything capable of being performed is either musical or poetic, or both musical and poetic.
Could be false. We know that all performances must be experienced in a fixed order and over a roughly fixed amount of time, but we don’t know that all performances are either musical or poetic––music and poetry are just referenced as two possible examples of performance.
Summary
The stimulus can be diagrammed as follows:
Notable Valid Inferences
If you can measure a the hull of a small boat accurately, then you used a line level.
A
The scientists did not accurately measure the hull’s dimensions because they had no experience measuring hulls.
Could be false. We only know that the scientists weren’t sure they had leveled the hull; we don’t know definitively that they did not do so. Also, we do not have enough information to guarantee the causal claim that (A) makes.
B
The scientists accurately determined the hull’s dimensions, provided that they leveled the hull.
Could be false. (B) can be represented as “level the hull→ measure accurately,” which reverses the sufficient and necessary conditions given in the sitmulus.
C
If the scientists did not accurately determine the hull’s dimensions, it was because they did not have a line level.
Could be false. (C) makes a causal claim that we cannot justify from the information in the stimulus.
D
The scientists were able to accurately record the hull’s dimensions only if they used a line level.
Must be true. We know that using a line tool is a necessary condition of measuring accurately.
E
If the scientists had measured the hull’s dimensions accurately, then at least one of them would have had experience measuring hulls.
Could be false. Experience with measuring hulls isn’t a necessary condition of measuring accurately.
"Surprising" Phenomenon
Why are small rats more likely than normal rats to suffer from heart problems, and large rats are less likely than normal to suffer form heart problems?
Objective
This is an EXCEPT question. The four wrong answers will help differentiate small rats from other rats in a way that makes them more likely to have heart problems, or it will help differentiate large rats from other rats in a way that makes them less likely to have heart problems.
A
Small rats are more likely than large rats to suffer from fatal diseases that tend to strike earlier than do heart problems.
This deepens our confusion. If small rats are more likely than large rats to die before getting heart problems, then we’d expect the overall rate of heart problems among small rats to be lower than for the other rats, who are more likely to survive to the age of getting heart problems.
B
Small rats generally have smaller blood vessels than do large rats, vessels that can more easily be clogged with fatty deposits.
If small rats have smaller blood vessels, which can be more easily clogged with fat, that’s a potential causal mechanism that could explain the smaller rats’ increased risk of heart problems.
C
The larger a rat is, the more successful it will be at defending itself, and therefore the less stressful its existence will be.
The smaller ones have more stress, which might lead to increased heart problems. The larger rats have less stress, which might lead to fewer heart problems. And the average rats are in the middle for stress, which might lead to being in the middle for heart problems.
D
In addition to being the leading cause of weak hearts in adult rats, malnutrition at early stages of development causes rats to be undersized.
This tells us malnutrition causes both a weak heart and smaller body size. This could explain why the smaller rats have more heart problems: those rats were more likely to be the malnourished ones.
E
Although large rats are no more active than rats of average size, they tend to be much more active than small rats, resulting in greater cardiovascular conditioning.
(E) establishes that small rats have less cardiovascular conditioning (meaning conditioning related to the heart) than the average and large rats. This helps explain why small rats have more heart problems than the other groups.