Summary
Large deposits of a rare mineral, nahcolite, formed in salty lakes over 50 million years ago during a time in history called the Eocene epoch. Experiments revealed that, in salty water, nahcolite can form only when the atmosphere contains at least 1,125 parts per million of carbon dioxide.
Strongly Supported Conclusions
The atmosphere contained at least 1,125 parts per million of carbon dioxide sometime during the Eocene epoch.
A
For most of the time since the Eocene epoch, the level of carbon dioxide in the atmosphere has been lower than it was during most of the Eocene epoch.
This comparative statement is not supported anywhere. The stimulus does not say anything about the relative levels of CO2 in the atmosphere during the Eocene epoch. It only implies that at some point in the epoch, the levels were high enough to form nahcolite.
B
Levels of carbon dioxide in the atmosphere fluctuated greatly during the Eocene epoch.
There is no evidence to suggest that these levels fluctuated. For all we know, they could still be the same today. All we know is that the levels were enough to form nahcolite.
C
Lakes were more likely to be salty during periods when the level of carbon dioxide in the atmosphere was at least 1,125 parts per million.
There is no support in the stimulus for whether a lake was more likely to be salty.
D
The atmosphere contained at least 1,125 parts per million of carbon dioxide during at least some part of the Eocene epoch.
The stimulus says that this mineral was formed during the Eocene epoch and that it could only have formed when the atmosphere contained at least 1,1125 parts per million of carbon. This is not only supported, but it must be true.
E
No significant deposits of nahcolite have formed at any time since the Eocene epoch.
This requires an assumption that the level of CO2 in the atmosphere has changed since the Eocene epoch. There is no support for this in the stimulus.
Speaker 1 Summary
Some writers explain Stalin’s misdeeds by characterizing his sanity during his later years as “paranoia” and “morbid suspiciousness.” However, Stalin’s cruelty was not more apparent during his later years than it was during the earlier periods of his rule. “Morbid suspiciousness” is a required characteristic for tyrants, because without it they would not remain in power.
Speaker 2 Summary
Objective
We need a statement that the critic and writers disagree on. They disagree whether certain characteristics of Stalin could explain why he was such a cruel leader. The writers think that Stalin’s characteristics could explain his misdeeds, while the critic thinks that Stalin was always a cruel leader.
A
whether Stalin should be held guilty of the cruel deeds attributed to him
Neither speaker expresses an opinion on this statement. We don’t know whether either speaker believes Stalin should be held guilty.
B
whether Stalin’s cruel misdeeds provide evidence of morbid suspiciousness
Neither speaker expresses an opinion on this statement. The writers would think the opposite relationship is true. For the writers, Stalin’s morbid suspiciousness explain his cruel misdeeds.
C
whether it is Stalin’s state of paranoia or rather his cruelty that gives the stronger reason for doubting his sanity
Neither speaker expresses an opinion on this statement. Neither speaker addresses whether it’s more likely paranoia or cruelty explain Stalin’s sanity.
D
whether tyranny tends to lead to cruelty
Neither speaker expresses an opinion on this statement. Only the critic addresses tyranny, and the critic does not conclude that tyranny usually leads to cruelty.
E
whether it was Stalin’s psychological state or rather his political condition that was the primary cause of his cruel misdeeds
The critic and the writers disagree on this statement. The writers agree that Stalin’s psychological state explain his cruel misdeeds, while the critic would agree that Stalin’s political status explain his cruel misdeeds.
Summarize Argument: Phenomenon-Hypothesis
The scientist hypothesizes Alzheimer’s disease is caused by a virus. This is based on a study where rats injected with blood from Alzheimer’s disease patients exhibited signs of a different neurological disorder which is caused by a virus.
Notable Assumptions
The scientist assumes that the rats developed Creutzfeldt-Jakob disease due to being injected blood from Alzheimer’s disease patients; if that virus came from elsewhere, then the hypothesis makes no sense. The scientist also assumes that the same virus that causes Creutzfeldt-Jakob disease causes Alzheimer’s disease. It would otherwise be purely coincidental that Alzheimer’s patients carry two separate disease-causing viruses.
A
Alzheimer’s disease in rats is not caused by a virus.
We have no evidence rats can even get Alzheimer’s. If anything, this seems to weaken the scientist’s argument.
B
Creutzfeldt-Jakob disease affects only motor nerves in rats’ limbs, not their brains.
We don’t care about how the disease affects rats. We care about where Creutzfeldt-Jakob disease came from.
C
The virus that causes Creutzfeldt-Jakob disease in rats has no effect on humans.
If it has no effect on humans, then it couldn’t cause Alzheimer’s disease. This weakens the scientist’s argument.
D
The symptoms known, respectively, as Creutzfeldt-Jakob disease and Alzheimer’s disease are different manifestations of the same disease.
Creutzfeldt-Jakob disease and Alzheimer’s disease are the same disease. Thus, a virus that causes one must cause the other, and we know that Creutzfeldt-Jakob disease in rats was caused by a virus.
E
Blood from rats without Creutzfeldt-Jakob disease produced no symptoms of the disease when injected into other experimental rats.
We need to strengthen the connection between a virus and Alzheimer’s disease. We can imagine rats without a virus don’t infect other rats.
Summary
Advertisers have learned that people are more likely to feel positively towards something if these things are connected by pictures to other things those people already feel positively towards.
Strongly Supported Conclusions
Therefore, advertisers are likely to design advertisements using pictures of things most people already like.
A
use little if any written prose in their advertisements
We don’t know if advertisers will use little prose. We only know that pictures help more than prose to develop a positive attitude about something.
B
try to encourage people to develop positive attitudes about products that can be better represented pictorially than in prose
We don’t know what types of products advertisers are likely to advertise. We only know something about the way in which advertisers are likely to advertise products generally.
C
place their advertisements on television rather than in magazines
We don’t know where advertisers are more likely to advertise. We only know that they are likely to advertise using pictures.
D
highlight the desirable features of the advertised product by contrasting them pictorially with undesirable features of a competing product
We don’t know what approach, if any, advertisers are likely to take towards competing products.
E
create advertisements containing pictures of things most members of the target audience like
Advertisements containing pictures that most members of the target audience like are likely to result in those people developing positive attitudes towards whatever is being advertised.