Summarize Argument: Phenomenon-Hypothesis
The zoologist hypothesizes that prehistoric European cave bears were not exclusively herbivores. This is supported by observations about bears’ heavy nitrogen levels, which are higher in meat-eating animals. Bone samples from cave bears contained heavy nitrogen levels as high as those in blood samples from modern, meat-eating bears.
Notable Assumptions
The zoologist assumes that heavy nitrogen levels in animals’ bones and blood are similar. The zoologist also assumes that heavy nitrogen levels did not change over time in the prehistoric bear samples, and that heavy nitrogen levels in the ecosystem back then were comparable to current levels.
A
Plants can also absorb heavy nitrogen from a variety of sources other than rainwater.
This is irrelevant. The argument has already established that plants absorb heavy nitrogen, so the exact source of the heavy nitrogen doesn’t matter.
B
The rate at which heavy nitrogen accumulated in the blood of Ice Age herbivores can be inferred from samples of their bones.
This is irrelevant, since the argument doesn’t make claims based on the rate of accumulation of heavy nitrogen in tissue, only the concentration of heavy nitrogen.
C
The same number of samples was taken from present-day bears as was taken from Ice Age cave bears.
This is irrelevant, because the exact number of samples doesn’t really make a difference. Either there were enough samples to be representative or there weren’t—either way, it would be equally possible to have the same number of samples.
D
Bone samples from present-day bears fed meat-enriched diets exhibit the same levels of heavy nitrogen as do their blood samples.
This strengthens by providing a closer comparison between cave bears and modern bears. If modern bears’ heavy nitrogen levels are identical between blood and bone, it’s more reasonable to draw conclusions by comparing cave bears’ bones and modern bears’ blood.
E
The level of heavy nitrogen in the bones of any bear fed a meat-enriched diet is the same as that in the bones of any other meat-eating bear.
This is irrelevant, since we can already be confident that the heavy nitrogen level in the modern bear samples is representative of a diet that includes meat.
Summarize Argument: Counter-Position
The consumer advocate argues that price gouging does not efficiently allocate goods to those with the most need but rather to those with the most money. While some economists believe that increasing prices during shortages effectively allocates goods by prioritizing those willing to pay more, the author disputes this. The author contends that willingness to pay is not proportional to need since some people simply cannot pay as much as others.
Identify Argument Part
This claim directly counters the economists' argument that those willing to pay more for a good must *need* the good more. The consumer advocate calls out this assumption by suggesting that those with the most money will end up with the desired good.
A
It disputes one explanation in order to make way for an alternative explanation.
This is not an alternative explanation. It is part of the consumer advocate’s reasoning that is used to reject the economist’s argument.
B
It is the overall conclusion of the argument.
This is not the conclusion of the argument. This supports the conclusion that a price increase will allocate goods to people with the most money.
C
It is a component of reasoning disputed in the argument.
This is not something that the author disputes. The consumer advocate believes this statement and uses it to dispute the economists’ reasoning.
D
It is a general principle whose validity the argument questions.
The argument does not question the validity of this statement. The author believes this statement and uses it to support the main conclusion.
E
It denies a claim that the argument takes to be assumed in the reasoning that it rejects.
This is a tough answer choice to parse through, but it’s dead on. This statement denies a claim (that willingness to pay a price reflects the level of need) that is assumed by the economists’ position, which the author wishes to reject.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that Alzheimer’s risk can be reduced by converting homocysteine into other substances. This is based on the fact that people with above-average levels of homocysteine have higher risk of being diagnosed with Alzheimer’s.
Notable Assumptions
The author assumes that there’s no other explanation for the correlation between above-average homocysteine levels and increased risk of Alzheimer’s.
A
Many Alzheimer’s patients have normal homocysteine levels.
A correlation between above-average homocysteine and Alzheimer’s allows for outliers. There can be Alzheimer’s patients with normal or even below-average homocysteine levels.
B
The substances into which homocysteine is converted can sometimes have harmful effects unrelated to Alzheimer’s disease.
If the effects are unrelated to Alzheimer’s, then they have no impact on the conclusion, which is focused only on whether Alzheimer’s can be reduced by converting homocysteine to those substances.
C
B vitamins and folic acid are not metabolized by the body very efficiently when taken in the form of vitamin-mineral supplements.
This just suggests B vitamins and folic acid should be taken in other forms besides vitamin-mineral supplements. The author never suggested any specific form in which we take B vitamins and folic acid.
D
People whose relatives contracted Alzheimer’s disease are much more likely to develop Alzheimer’s than those whose relatives did not.
This suggests that there’s also a genetic component to Alzheimer’s. But there could be a genetic component to having higher homocysteine levels. In addition, it’s possible for there to be multiple, independent causes of Alzheimer’s.
E
Alzheimer’s disease tends to increase the levels of homocysteine in the blood.
This provides an alternate explanation for the correlation observed. If Alzheimer’s increases homocysteine, we’d expect people with Alzheimer’s to have higher levels of homocysteine, even if homocysteine doesn’t cause Alzheimer’s.
Sociologist: Television, telephones, and other electronic media encourage imprecise, uncritical thinking. Yet critical thinking is the only adequate protection against political demagogues, who seek to exploit people by presenting emotionally loaded language as an objective description of reality.
Summary
Television, telephones, and other electronic media encourage uncritical thinking. However, critical thinking is the only adequate protection against political demagogues, who seek to exploit people by presenting emotionally loaded language as an objective description of reality.
Notable Valid Inferences
A strong system of government cannot provide adequate protection against the influence of political demagogues.
A
There are no political demagogues in some highly technological societies.
Could be true. We don’t have any information about highly technological societies in the stimulus. It is possible that these societies do not have political demagogues.
B
Political demagogues are not the only ones who seek to exploit people by presenting emotionally loaded language as an objective description of reality.
Could be true. The stimulus does not tell us that political demagogues are the only ones who seek to exploit people. It is possible that there are others in addition to political demagogues with the same or similar objectives.
C
Highly emotional people are more easily exploited than less emotional people.
Could be true. The stimulus does not give us any information about what kinds of people are more easily exploited. It is possible highly emotional people are more easily exploited than less emotional people.
D
The mere presence of an orderly system of government in a society provides adequate protection against political demagogues.
Must be false. The stimulus tells us that critical thinking is the only adequate protection against political demagogues. Everything else, therefore, is inadequate.
E
The mere presence of electronic communications technology in a society provides adequate protection against the erosion of media freedoms.
Could be true. The stimulus is restricted to protection against political demagogues. We cannot assume protection against political demagogues is the same thing as protection from the erosion of media freedoms.