Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the regular sequence of ice ages Earth has experienced since 800,000 years ago are caused by Earth’s passing through clouds of cosmic dust. According to this theory, the cosmic dust enters Earth’s atmosphere, which dims the sun, causing an ice age.
Notable Assumptions
The author assumes there’s no other explanation for what causes Earth’s regular sequence of ice ages. The author assumes that the occurrence of ice ages is correlated with Earth’s passage through clouds of cosmic dust.
A
Earth did not pass through clouds of cosmic dust earlier than 800,000 years ago.
This strengthens by defending the argument from the possibility that passage through cosmic dust occcurred before the ice ages starting to occur.
B
Two large asteroids collided 800,000 years ago, producing a tremendous amount of dense cosmic dust that continues to orbit the Sun.
This helps establish that the dense cosmic dust the author’s hypothesis requires actually exists and correlates with the beginning of the ice ages.
C
Earth’s average temperature drops slightly shortly after volcanic eruptions spew large amounts of dust into Earth’s atmosphere.
This strengthens by showing that dust in Earth’s atmosphere can reduce Earth’s average temperature. This makes the author’s theory about dust causing ice ages more plausible. Although (C) is about volcanic dust, it still shows that dust in atmosphere can cool the Earth.
D
Large bits of cosmic rock periodically enter Earth’s atmosphere, raising large amounts of dust from Earth’s surface.
(D) tells us that cosmic rock periodically enters the atmosphere. But does the Earth get colder after this happens? We don’t know. Do these periodic entries of cosmic rock coincide with Earth’s ice ages? We don’t know. (D) has no impact.
E
Rare trace elements known to be prevalent in cosmic debris have been discovered in layers of sediment whose ages correspond very closely to the occurrence of ice ages.
This provides evidence of a correlation between cosmic debris and the occurrence of ice ages.
Summary
The argument concludes that the economy is doing badly for two reasons: the first because the real estate market is in a slump and the second because car sales are low. If the economy were healthy, at least one of these two phenomena would not occur.
Strongly Supported Conclusions
If the economy were healthy then either car sales are not low, the real estate market is not in a slump, or both.
A
If car sales are at their lowest in years, then it is likely that the economy is doing badly.
We don’t know if low car sales alone is sufficient for a bad economy. Rather, the argument suggests that low car sales combined with a real estate slump lead to a bad economy.
B
If the economy is doing badly, then either the real estate market or the car sales market is not healthy.
We know that low car sales combined with a real estate slump are sufficient for a bad economy, but we do not know if these are the only two factors sufficient for a bad economy. A necessary condition’s occurrence does not imply the sufficient condition’s occurrence.
C
If the real estate market is healthy, then it is likely that the economy as a whole is healthy.
We don’t know what conditions are sufficient for a healthy economy. There could be other factors outside of the real estate market and car sales that lead to a bad economy.
D
If the economy is in a healthy state, then it is unlikely that the real estate and car sales markets are both in a slump.
The argument states that if car sales are not low or the real estate market is not in a slump, the economy is likely to be healthy. Therefore, if the economy were healthy it is likely that at least one of these phenomena occurred.
E
The bad condition of the economy implies that both the real estate and the car sales markets are doing badly.
We know that low car sales combined with a real estate slump are sufficient for a bad economy, but we do not know if these are the only two factors sufficient for a bad economy. A necessary condition’s occurrence does not imply the sufficient condition’s occurrence.
Summarize Argument
The author concludes that the Acme retirement plan is probably a good plan for anyone with retirement needs similar to the Economic Merit Prize winners. This is based on the fact that each of the winners from the past 25 years is covered by the Acme retirement plan. The author interprets this fact as showing that the prize-winners have recognized that the plan is a good one for them.
Identify and Describe Flaw
The author assumes that the reason the winners have the Acme plan is that they believe the plan is a good one for them. This overlooks the possibility that they have the plan for some other reason unrelated to their perception of the plan’s quality. The author also assumes that if the winners believe the Acme plan is good for them, then that constitutes evidence that the plan actually is good for people with similar retirement needs.
A
It ignores the possibility that the majority of Economic Merit Prize winners from previous years used a retirement plan other than the Acme plan.
This possibility does not undermine the argument because prize-winners with other plans might simply have different retirement needs from the prize-winners the author cites to. Also, the author does not assert that the Acme plan is the best, or that it is the only good plan.
B
It fails to address adequately the possibility that any of several retirement plans would be good enough for, and offer a financially secure future to, Economic Merit Prize winners.
This possibility does not undermine the argument because the author does not assume that the Acme plan is the best. He states only that the prize-winners recognize that the Acme plan is “probably a good plan” for people wit similar needs. But there can be other good plans, too.
C
It appeals to the fact that supposed experts have endorsed the argument’s main conclusion, rather than appealing to direct evidence for that conclusion.
The main concluson is that the Acme plan is probably a good plan for anyone with retirement needs similar to those of the prize-winners. The author does not state or assume that the prize-winners endorse that specific conclusion.
D
It takes for granted that some winners of the Economic Merit Prize have deliberately selected the Acme retirement plan, rather than having had it chosen for them by their employers.
The author assumes that the reason some prize-winners have the Acme plan is that they perceive it to be good for them. This requires that the plan was not forced upon them. If it was, then the the fact some of them have the Acme plan does not tell us about their perception of it.
E
It presumes, without providing justification, that each of the Economic Merit Prize winners has retirement plan needs that are identical to the advertisement’s intended audience’s retirement plan needs.
The author’s conclusion is limited to “anyone with retirement needs similar to [the prize-winners’].” This acknowledges that some people might not have identical retirement needs.
Summarize Argument: Phenomenon-Hypothesis
Scientists hypothesize that P-fat is necessary for developing eyesight. This is because babies fed formulas low in P-fat have worse eyesight than babies fed mother’s milk, which is high in P-fat. Moreover, premature babies have worse eyesight than babies carried to term.
Notable Assumptions
The scientists assume that P-fat is the only relevant difference between formulas and mother’s milk. If there was some other difference, then that difference could just as well account for the difference in eyesight. The scientists also assume that babies carried to term receive more P-fat than those born prematurely.
A
Adults whose diets lack P-fat tend to have worse eyesight than those whose diets are high in P-fat.
We’re talking about developing eyesight. We don’t care about maintaining eyesight.
B
A fetus typically receives high levels of P-fat from the mother during only the last four weeks of pregnancy.
Premature babies have worse eyesight than babies carried to term because they miss out on a critical fetus stage: the last four weeks, where fetuses receive high levels of P-fat. This strengthens the connection between P-fat and developing eyesight.
C
Babies whose mothers have poor eyesight do not tend to have poor eyesight themselves.
The scientists agree eyesight isn’t totally genetic. However, we’re specifically trying to strengthen the connection between P-fat and eyesight. This doesn’t do that for us.
D
Babies generally prefer mother’s milk to formulas low in P-fat.
We don’t care what babies prefer.
E
The eyesight of a fetus develops during the last trimester of pregnancy.
This weakens the scientists’ hypothesis. If eyesight develops during the last trimester, then the postnatal difference between formula and mother’s milk wouldn’t be relevant.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that a certain gene variant causes an inclination toward thrill-seeking behavior. This is based on the fact that the author’s research indicates that children who engage in impulsive behavior similar to adult thrill-seeking behavior are twice as likely as other children to have that gene variant.
Notable Assumptions
The author assumes that a correlation between the gene variant and impulsive behavior proves a causal relationship. The author also assumes that the cause of impulsive behavior in children also causes adult thrill-seeking behavior.
A
Many impulsive adults are not unusually sensitive to dopamine.
The author never suggested every adult has the gene variant. So, the fact many impulsive adults aren’t unusually sensitive (and therefore might not have the gene variant) doesn’t undermine the author’s reasoning.
B
It is not possible to reliably distinguish impulsive behavior from other behavior.
This shows that the alleged correlation shown by the author’s research doesn’t reliably tell us about impulsive behavior. If we can’t be sure that the author’s research identified impulsive behavior, that reduces the support provided by the research for a causal relationship.
C
Children are often described by adults as engaging in thrill-seeking behavior simply because they act impulsively.
The argument is about alleged impulsive behavior in children and adult thrill-seeking behavior. Whether children’s behavior is called thrill-seeking doesn’t affect the potential cause of impulsive behavior or adult thrill-seeking behavior.
D
Many people exhibit behavioral tendencies as adults that they did not exhibit as children.
The author never suggested that every child with impulsive behavior grows up to exhibit adult thrill-seeking behavior. So, even if many adults end up not impulsive and not thrill-seeking, that doesn’t undermine the underlying correlation the author observed.
E
The gene variant studied by the scientist is correlated with other types of behavior in addition to thrill-seeking behavior.
This suggests the gene variant might cause other types of behavior in addition to thrill-seeking behavior. But it doesn’t suggest the gene variant might not cause thrill-seeking behavior. (E) could have weakened if the thrill-seeking was correlated with a different gene.
Summarize Argument: Counter-Position
In this argument, the sociologist is arguing that one can support both political democracy and marketplace regulation. To support this, the sociologist cites the distinction between the private consumer, who makes individual decisions, and the public citizen, who makes decisions that consider a broader community. Because people are considering different factors in the market and the voting booth, support for market regulation and democratic sovereignty can coexist.
Identify Conclusion
The sociologist concludes that support for two ideas that some view as contradictory can coexist: “Supporters of political democracy can also support marketplace regulation.”
A
Voters think of themselves as members of a community, rather than as isolated individuals.
This idea is implied when the argument says that voters ask “What do we want?” However, this implication is not the main conclusion; it provides some support for the distinction made between voters and customers.
B
Unregulated markets are incompatible with democratic sovereignty.
Our conclusion discusses what ideas people can support; this answer says that two institutions/structures themselves (unregulated markets and democratic sovereignty) are (in)compatible. We are want to know that support for two ideas is compatible.
C
Where there is democratic sovereignty there should be unregulated markets.
This answer choice is the conclusion made by some economists; this is the claim that the sociologist’s conclusion works to refute.
D
Private consumers are primarily concerned with their own self-interest.
This idea is implied when the argument says that consumers ask “What do I want?” However, this implication is not the main conclusion; it provides some support for the distinction made between voters and customers.
E
Opposition to unregulated markets is consistent with support for democracy.
This is the conclusion of the argument. This answer is a paraphrase of the last sentence, which we identified as the main conclusion of the argument. The rest of sociologist’s argument works to provide support for this idea.