A
We have no plausible chronology of most of the events for which attempts have been made by historians to determine the right date.
B
Some of the events for which there are conflicting chronologies and for which attempts have been made by historians to determine the right date cannot be dated reliably by historians.
C
Attaching a reliable date to any event requires determining which of several conflicting chronologies is most likely to be true.
D
Determining independently of the usual sources which of several conflicting chronologies is more likely to be right is an ineffective way of dating events.
E
The soundest approach to dating an event for which the usual sources give conflicting chronologies is to undermine the credibility of as many of these sources as possible.
Biologist: Some speculate that the unusually high frequency of small goats found in island populations is a response to evolutionary pressure to increase the number of goats so as to ensure a diverse gene pool. However, only the reproductive success of a trait influences its frequency in a population. So, the only kind of evolutionary pressure that can reduce the average size of the members of a goat population is that resulting from small goats achieving greater reproductive success than their larger cousins.
Summary
The biologist refutes the view that the high frequency of small goats on islands is due to evolutionary pressure to increase the number of goats. Why is this wrong? The only way a trait can increase in frequency is through reproductive success, Therefore, the only evolutionary pressure that could cause this phenomenon is small goats achieving greater reproductive success.
Strongly Supported Conclusions
The biologist considers the speculations she refers to to be incorrect.
Small goats have greater reproductive success in island populations than larger goats.
Ensuring a diverse gene pool does not qualify as evolutionary pressure.
A
The evolutionary pressure to ensure a diverse gene pool could have the effect of increasing the frequency of a gene for small size.
Anti-supported. The biologist refutes this point. She says only reproductive success would qualify as evolutionary pressure.
B
The unusual frequency of small goats in island populations is not a result of the greater reproductive success small goats possess when space is limited.
Anti-supported. The biologist claims that the only thing that can reduce the average size of the population is greater reproductive success for small goats. This may or may not be due to the small space.
C
Contrary to what some believe, large goats achieve greater reproductive success than small goats even when space is limited.
Unsupported. There is no support for the actual reproductive success rates by goat size. The biologist is advocating the point that the smaller goats must achieve greater reproductive success in order to decrease the average size of the goats.
D
The evolutionary pressure to ensure a diverse gene pool does not have the effect of increasing the frequency of a gene for small size.
Strongly supported. The author dismisses this claim on the grounds that it does not impact reproductive success, the only way to influence frequency. Therefore, ensuring a diverse gene pool cannot have the effect of increasing the frequency of the gene for small size.
E
A diverse gene pool cannot be achieved in a goat population unless the average size of its members is reduced.
Unsupported. There is no information as to how a diverse gene pool can or cannot be achieved. That was only part of a theory that was dismissed.
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A
The threshold can be lowered by lowering the dietary consumption of cholesterol and fat.
B
People who consume an average North American diet cannot increase their consumption of cholesterol and fat without dramatically increasing their serum cholesterol levels.
C
People who consume half as much cholesterol and fat as in the average North American diet will not necessarily have half the average serum cholesterol level.
D
Serum cholesterol levels cannot be affected by nondietary modifications in behavior, such as exercising more or smoking less.
E
People who consume less cholesterol and fat than the threshold cannot reduce their serum cholesterol levels.
This is an Argument Part question, so we have to describe the role played in the argument by the statement that "many major cities had similar ratios of police officers to citizens, yet diverged widely in their crime rates."
Like all other LR questions, we try to identify the conclusion and the premises first.
This passage is sneaky. It start by telling us that "many people believe X". Normally, when we encounter a passage that starts like that, what's the upshot? What's the conclusion?
That those people are wrong in their moronic beliefs.
I mean, if I just told you "Look man, I know that lots of people believe X, but Y". You actually get a lot of information out of this right?
You must hear me communicating to you that those people are wrong. The structuring of that sentence, using "but" says that much.
In this passage, we're suppose to hear that increasing the number of police officers is not the only way to remedy crime. That's the unspoken conclusion.
Why should we believe it?
Just look at all these major cities with about the same number of cops to citizens (say, 1 cop for every 1,000 citizens). Yet, they all have very different levels of crime.
We are prodded to draw the conclusion that there must be some other factor that influence the level of crime. In other words, number of cops isn't the only factor. That's answer choice (E).
(C) is wrong because it's not clear what counts as a "proof". If they mean validity, then certainly this argument doesn't meet that high standard. Additionally, (C) says there are other factors that are "more important" than the number of cops. We have some information that there exists other factors, maybe. But we have no information about the relative causal strength of those factors. Which one is more important?
(D) is wrong because the idea of "having no effect" is very different from the idea of "being one causal component amongst many".
A
establish that the number of police officers does not need to be increased
B
illustrate the need for increasing the number of police officers in major cities
C
prove that there are factors other than the number of police officers that are more important in reducing the crime rate
D
demonstrate that there is no relation between the number of police officers and the crime rate
E
suggest that the number of police officers is not the only influence on the crime rate
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