The epidemiologist’s argument improperly assumes that the cancer death rates were similar in the two towns ten years ago. While the rates in Maple Grove have INCREASED much more than in Fernland, what if they were much lower to begin with. Just because the rate has increased more in Maple Grove, it could easily be lower today than in Fernland. Answer choice "Whether Fernland and Maple Grove had similar cancer death rates 10 years ago." properly points out this assumption and is thus the correct answer. For "Whether the population in Maple Grove has increased dramatically in the past decade.", population growth is unimportant because it is a per capita rate. The smoking issue is a red herring in this problem (tries to steal your attention from the major data problem), so "Whether smoking is the primary cause of cancer in Fernland." and "Whether Maple Grove has ever introduced an anti-smoking initiative." are both wrong. For "Whether most cancer victims in Maple Grove survive more than 10 years.", the length of survival is also immaterial to the major data problem isolated above. Answer is "Whether Fernland and Maple Grove had similar cancer death rates 10 years ago.".

As you deconstruct this argument, you should notice a classic case of mistaking correlation (two things occur together) for causation (one causes the other). Here you're told that people who exercise regularly have a lower incidence of respiratory illness, and then the conclusion is that regular exercise helps prevent respiratory illness.

But why can't that be the other way around? Whenever a question is structured as "X and Y happen together, so X likely causes Y" you should be on the lookout for an answer choice that suggests that, actually, Y is the thing that causes X.

Answer choice "People with respiratory illnesses are generally told by doctors that they must limit or cease their aerobic exercise routines." here supplies exactly that: if people who have respiratory illness are unable to exercise, that's a possible reason for the statistics (exercise and respiratory health occur together) to be true. So by providing an alternate explanation for the premises, "People with respiratory illnesses are generally told by doctors that they must limit or cease their aerobic exercise routines." shows that the conclusion is not necessarily true. "People with respiratory illnesses are generally told by doctors that they must limit or cease their aerobic exercise routines." is correct.

"Some respiratory illnesses are hereditary and therefore minimally affected by lifestyle choices." is incorrect because the conclusion is so soft, that exercise "can be helpful in preventing" respiratory illness. Even if some respiratory illnesses cannot be prevented, choice "Some respiratory illnesses are hereditary and therefore minimally affected by lifestyle choices." does not prohibit exercise from preventing other respiratory illnesses. Note also that "Some respiratory illnesses are hereditary and therefore minimally affected by lifestyle choices." says that the hereditary respiratory illnesses are minimally affected by lifestyle choices. "Minimally affected" still allows for lifestyle choices to have an impact, which is consistent with "can be helpful" in preventing these illnesses.

"The amount of air pollution, a common cause of respiratory illness, has increased dramatically since the 1950s." and "The lengths of the average workday and commute have increased markedly since the 1950s, leaving the average person with less time for aerobic exercise." are wrong for similar reasons: they are each overruled by the facts, which state that exercise and a lack of respiratory illness have remained correlated over time, even if respiratory illness is increasing due to pollution "The amount of air pollution, a common cause of respiratory illness, has increased dramatically since the 1950s." or people in general are exercising less "The lengths of the average workday and commute have increased markedly since the 1950s, leaving the average person with less time for aerobic exercise.". You still have facts from the argument that those who do find time to exercise have less respiratory illness than those who do not, so "The amount of air pollution, a common cause of respiratory illness, has increased dramatically since the 1950s." and "The lengths of the average workday and commute have increased markedly since the 1950s, leaving the average person with less time for aerobic exercise." are countered by the given information.

"Recent studies have debunked the conventional wisdom that aerobic exercise is an effective preventer of heart disease." misses the specific scope of the conclusion, which is only about respiratory illness. The fact that exercise doesn't prevent heart disease doesn't factor in to a discussion about respiratory issues. Because heart issues and respiratory issues are two completely different categories, "Recent studies have debunked the conventional wisdom that aerobic exercise is an effective preventer of heart disease." does not directly address the conclusion about respiratory issues.

An important gap in logic on this question exists between premises: we’re told that if a parcel isn’t SCANNED by 4:30, it will not be included for overnight delivery. And we’re told that if the prototypes in the package are not received by the next day, the client will cancel its account.  The concluding sentence says that because James DROPPED OFF the package by 4:00, ahead of the 4:30 SCANNING deadline, the company will not lose the account.

Now, notice the big gap here between “DROPPED OFF” and “SCANNED” - is it sufficient to say that because James dropped off the package it will definitely be scanned in time?  Dropped off and scanned are two different things. So the answer “Any parcel dropped off before the overnight shipping deadline will be scanned prior to the deadline” is important to connect those dots.

Recognize that the argument contains other gaps, too: the client wants the prototypes by the next morning, but does “scanned for overnight delivery” guarantee “received by morning?”  It does not, but no answer choices deal with that gap in logic.

The argument jumps from the idea that these utilities are included for sales reasons to suggesting that they save the computer manufacturer money. Something to link the function of these programs to savings is necessary -- and that is exactly what answer choice "Computer viruses, disk fragmentation, and out-of-date applications are three major sources of warranty claims against computer manufacturers." offers. It is the correct answer. Answer choice "Surveys indicate that free software packages are very important to consumers." may initially appear attractive because of the original statement that free software is included to drive sales, but the argument focuses on cost savings to the manufacturer. Answer choices "Many anti-virus programs offer little, if any, real protection." and "Disk defragmentation is an important routine task that should be performed at least once per month." offer interesting but irrelevant information. Answer choice "Even though computer manufacturers buy these utility programs in bulk, they are still a significant cost to the manufacturer." would, if anything, weaken the argument.

In this Weaken question, the conclusion is that type 1a supernovae are an effective way of measuring distances. The reason is that they have a predictable brightness that fades over distance in a predictable way. Observing and measuring this brightness then allows the distance to be reconstructed. If answer choice "Large clouds of interstellar dust and ionized hydrogen can absorb the light emitted by type 1a supernovae.", the correct answer, were true, however, external factors could create significant variations in the way that the light is observed from Earth, and the use of the brightness observations to gauge distance would seem to be unreliable. Answer choices "Type 2 supernovae are discovered to be even more dramatically variable in their brightness than previously thought." and "Some supernovae exhibit very unusual spectral classifications and changes in brightness, and do not fit into the existing categories." talk about other sorts of supernovae which are not the type we are considering and are, therefore, out of scope. Answer choice "Models explaining the causes of type 1a supernovae are altered to include an updated understanding of the role played by carbon fusion." discusses the model explaining how the supernova works but says nothing about modifying the predictions of how bright the explosion is. Answer choice "A new telescope is able to measure the brightness of several thousand type 1a supernovae with an unprecedented level of precision." does not say anything about the results of the telescope and therefore has no effect on the assumption.

In this strengthen question, take careful note of the oil executive's conclusion, which is that the increase in reported oil spills (he concedes this is a fact) has occurred because it is easier to detect small oil spills, not because there are more oil spills. In other words, the total number of oil spills is the same, and the increased number of reports of them is due to the more-frequent reporting of small spills.

Note how correct answer "The number of large and medium oil spills has remained roughly constant over the last three decades." directly strengthens that: if you know (from the argument) that there are more reported spills overall, and you know (from choice "The number of large and medium oil spills has remained roughly constant over the last three decades.") that the number of large and medium spills is unchanged, then the increase has to have come from the reporting of those small spills. "The number of large and medium oil spills has remained roughly constant over the last three decades." limits the increase to the smaller spills, and therefore furthers the executive's argument.

Note that with choice "The size of the average oil spill has decreased over the last three decades.", the conclusion isn't that there are more small oil spills total but that there have been more reported. So the fact that the average spill is smaller doesn't directly relate to the executive's argument. Furthermore, even if the average reported spill were smaller, that doesn't necessarily mean that there are more small spills being reported - it could just be that each of the larger and medium spills reported have been smaller (maybe they were better-controlled than in the past, for example).

Choice "Because of improved logistics, the average distance a barrel of oil travels to its destination has decreased by 40% over the last three decades." might seem to suggest a reason that there are fewer spills (there is less time/space that each barrel spends in transit) but this misses the general purpose of the argument, which relates to the detection of small spills. The argument isn't that there are fewer transportation-related spills, but that the increase in reported spills comes primarily from the detection of smaller spills.

Choices "The cost required to clean up the average oil spill has decreased by over 20% over the last three decades." and "The average oil company spends nearly twice as much today on anti-spill equipment as it spent three decades ago." each attempt to use cost as proxy for safety - "The cost required to clean up the average oil spill has decreased by over 20% over the last three decades." wants you to think that because the cost of cleanup is down, the spills must be less frequent or smaller, but that's not necessarily the reason. Perhaps cleanup technology has just gotten less expensive. Similarly "The average oil company spends nearly twice as much today on anti-spill equipment as it spent three decades ago." wants you to think that because companies are spending more to prevent spills, spills have decreased or stayed the same. But that's not necessarily the case: what if inflation is higher and the companies are spending less in "real" terms and more nominally because of the currency, for example?

Only choice "The number of large and medium oil spills has remained roughly constant over the last three decades.", which is correct, directly relates to the detection of small spills.

Whenever you are asked for an answer choice that will weaken a given argument or conclusion, remember that you should first seek to understand the argument and then you should look to find the gap between the premises of the argument and its conclusion.

You are told here that since 1950 the number of women diagnosed with postpartum depression in Heranita has increased. Because of this, the advocate suggests that the country improve the women's health care system so that women do not have to experience the symptoms of postpartum depression. Already you should see that there are a few gaps here - what if women have symptoms but aren't diagnosed? What differentiates postpartum depression from regular depression?

Only "Until 1970, most doctors were not specific in their diagnoses but instead grouped all types of depression together." addresses one of those gaps. If cases of postpartum depression were once described under the general umbrella of "depression", then it is impossible to know if postpartum depression is in fact on the rise.

Among the other answers, "The amount of spending on women’s health has increased since 1950." can be eliminated since just because women's health has increased, there is no telling whether spending to prevent postpartum depression has increased. "Rates of postpartum depression are not included in official government statistics." can be eliminated since another agency outside the government might keep track of rates of postpartum depression so this doesn't affect the argument. "The minimum threshold of symptoms women experience before they can be diagnosed has increased since 1950." can be eliminated since just because the minimum severity of symptoms required for diagnosis has increased doesn't mean that the rate has not increased. "It is likely that cases of postpartum depression are underreported in Heranita." can be eliminated because it would in fact strengthen the argument posed.

Your goal in this "Explain the Paradox" question is to find a reason why environmentalists would support the expansion of a landfill that comes with groundwater pollution problems over the construction of a new landfill that would come with no groundwater pollution problems. As you anticipate what you would want to see from a correct answer, you might think about:

-What if the new landfill doesn't have groundwater pollution problems, but instead creates other pollution problems?

-What is leaving the old landfill would create even bigger problems than staying there?

Choice "Without continued operation and maintenance, the current landfill's groundwater pollution rate would more than double. " works well with the second option: if leaving the current landfill would create a much bigger environmental problem than staying there would, that is a reason that those who care about the environment would vote to stay. Choice "Without continued operation and maintenance, the current landfill's groundwater pollution rate would more than double. " is correct.

Choices "Several recent ecological studies suggest that the rate of pollution from the current landfill is lower than had initially been reported." and "Groundwater pollution is less of a concern in Sturgeon County than is air pollution from the county's coal-fired power plants." may be tempting, but each comes with a significant flaw. Note that "Several recent ecological studies suggest that the rate of pollution from the current landfill is lower than had initially been reported.", while reducing the impact of the pollution problem with the current landfill, still leaves the ballot proposals as a comparison between "some pollution" and "no pollution," so you still don't have a reason that the environmentalists would pick "some" when "none" is an option. And while choice "Groundwater pollution is less of a concern in Sturgeon County than is air pollution from the county's coal-fired power plants." may seem to hit the standard of "what about other types of pollution other than just groundwater?" note that the argument doesn't provide any reason to suspect that the new landfill would create more air pollution. With all known information, it's still a comparison between "some pollution" and "no pollution."

Choice "Polling data indicates that the new landfill proposal is unlikely to pass without support from prominent environmental activists.  " is irrelevant - what the polls suggest is no reason for the environmentalists to choose pollution over no pollution. And choice "The site of the proposed new landfill is privately-owned land that the county would have to purchase during a period of high real estate values." is carefully invalidated by the phrase "same amount" in the argument - if each plan costs the same amount, then the expense of the land for the new landfill isn't a reason to not choose it.

In this “explain the paradox” question, you are told that for albatrosses, placing geolocation tags in the middle of the back of the bird interferes less with bird movement than does placing geolocation tags under the tail feathers. However most studies on birds in general show the opposite to be true. In looking to resolve this paradox, you should ask yourself - what makes albatrosses and soaring birds special compared to other birds studied?

Choice "Albatrosses are much larger than other soaring birds, so geolocation tags make up less of their total body weight." makes a distinction between albatrosses and other soaring birds. Since both albatrosses and soaring birds are addressed together, this doesn’t given information as to why these birds are more affected by one geolocation tag placement and other birds are more affected by another. Eliminate "Albatrosses are much larger than other soaring birds, so geolocation tags make up less of their total body weight.".

Choice "Geolocation tagging practices have changed over time to include smaller devices." can be eliminated because it deals with change over time - something that isn’t addressed within the question. All the studies referenced could have been in the last year or they could have been over the course of 20 years. There’s no way of knowing, so there’s no way of knowing whether this would have an affect on placement.

If choice "Soaring doesn’t involve the tailfeathers, so geotag placement there will not affect movement." was true, then soaring birds would be less affected by placing the geolocation tags than would other flying birds, not more.

Choice "Albatrosses tend to expend less energy than other birds while soaring because of their large wingspan." can also be eliminated. The question deals with relative interference with movement, not the absolute amount of energy expended.

Choice "The majority of studies were done on penguins, which don’t fly but do spend much of their time hunting underwater." is correct. You are told that geolocation tags can affect drag (which occurs in the water) and lift (which occurs in the air). Since you are told that penguins can’t fly but that they do swim, you can conclude that only drag matters, so if the majority of studies were done on penguins, then the majority of studies would say that the ideal placement is under the tailfeathers.

For Explain the Paradox questions, remember that you need to find an answer that bridges the gap between two seemingly contradictory facts by explaining why both can be true. Don't worry about anticipating the correct answer if you don't automatically see it - just look for the gap that needs to be bridged and find an answer choice that does so.

The argument states that even though more Gala apples are produced than any other apple, more Granny Smith apple trees are sold each year. You are looking for an answer that would result in more Granny Smith trees being sold but still ensure that production of Gala apples was greater than that of any other tree. The only answer that allows for this is "Gala apple stems are often “grafted” onto Granny Smith tree trunks after purchase so that the trees produce Gala apples rather than Granny Smith ones.". If Gala tree stems are grafted onto Granny Smith trunks, so that the trees produce Gala apples rather than Granny Smith ones, that means that at least some of the Granny Smith trees being sold are actually used to produce Gala apples. Choice "Gala apple stems are often “grafted” onto Granny Smith tree trunks after purchase so that the trees produce Gala apples rather than Granny Smith ones." is correct.

Among the other answers, choice "Many Granny Smith apples are produced for decorative rather than culinary purposes, especially in the northeastern United States." can be eliminated because the use of the apple isn't important, just whether or not it's produced. Choices "Many Gala apple trees die before they reach apple producing maturity because their stems are not as hardy as those of Granny Smith apple trees." and "Because the varieties are so similar, many nurseries list sales of both Gala and Pink Lady apple trees as Gala apple tree sales." would actually go counter to what you are trying to accomplish. If "Many Gala apple trees die before they reach apple producing maturity because their stems are not as hardy as those of Granny Smith apple trees." is true, then in order to produce enough apples farmers would have to purchase more Gala trees rather than fewer. Similarly, if "Because the varieties are so similar, many nurseries list sales of both Gala and Pink Lady apple trees as Gala apple tree sales." is true then that means that the number of Gala trees sold is actually underreported, creating a larger contradiction than was previously indicated. Choice "There is no difference between the average spoilage time of an apple coming from a Gala tree and one coming from a Granny Smith tree." can also be eliminated. Spoilage time can only affect the number of apples sold (since some will not make it to market) NOT the number of apples produced, which is what the question is looking for.