Summary
Coffee and tea contain a substance (methylxanthines) that leads to temporary increases in the body’s production of vasopressin. Vasopressin causes clumping of blood cells, and this clumping is more pronounced in women than in men. Increased clumping of blood cells is probably why, compared to men, women have a significantly higher risk of complications following angioplasty, which is an operation for clearing clogged arteries.
Strongly Supported Conclusions
In at least one respect, coffee and tea may be more dangerous to women than to men.
Drinking excessive amounts of coffee or tea may lead to increased risk of complications following angioplasty.
Drinking excessive amounts of coffee or tea may lead to increased risk of complications following angioplasty.
A
Men, but not women, should be given methylxanthines prior to undergoing angioplasty.
Unsupported. We’re not given a reason anyone should be given methylxanthines ever. Maybe there’s nothing positive about methylxanthines.
B
In spite of the risks, angioplasty is the only effective treatment for clogged arteries.
Unsupported. We’re told angioplasty is one technique for unclogging arteries, but we don’t know whether there are any other techniques that could be effective.
C
Women probably drink more coffee and tea, on average, than do men.
Unsupported. The stimulus tells us about the effects of coffee and tea, but not about the number or proportion of men or women who drink coffee and tea.
D
Prior to undergoing angioplasty, women should avoid coffee and tea.
Strongly supported. Women face a higher risk of complications following angioplasty because clumping of blood cells is more pronounced in their bodies. Since coffee/tea increase substances that lead to clumping, there’s reason for women to avoid coffee/tea before angioplasty.
E
Angioplasty should not be used to treat clogged arteries.
Unsupported. Angioplasty may lead to complications, but that doesn’t imply that the technique is not worth the risk of complications.
Artists have different ways of producing contours and hatching, and analysis of these stylistic features can help to distinguish works by a famous artist both from forgeries and from works genuinely by other artists. Indeed, this analysis has shown that many of the drawings formerly attributed to Michelangelo are actually by the artist Giulio Clovio, Michelangelo’s contemporary.
Summary
Artists have different ways of producing contours and hatching. Analyzing these stylistic features can help distinguish works by a famous artist from forgeries and from works by other artists. This analysis has shown some drawings formerly attributed to Michelangelo are actually by the artist Giulio Clovio.
Notable Valid Inferences
There is a noticeable difference between the stylistic features of Giulio Clovio and Michelangelo.
A
Contours and hatching are the main features that distinguish the drawing styles of different artists.
Could be false. To say that contours and hatching are the main features is too extreme. We only know that contours and hatching are some features to help distinguish works of art. It is possible there are many more features than these.
B
Many of the drawings formerly attributed to Michelangelo are actually forgeries.
Could be false. We only know that some of these former drawings are actually Giulio Clovio’s, but we can’t assume they are forgeries. It is possible that these drawings were only mistakenly attributed to Michelangelo, and Giulio Clovio never intended to forge the drawings.
C
No forgery can perfectly duplicate the contour and hatching styles of a famous artist.
Could be false. We only know that analyzing contours and hatching helps to distinguish works between famous artists and forgeries, but we can’t assume that this analysis is foolproof.
D
The contour and hatching styles used to identify the drawings of Clovio cited can be shown to be features of all Clovio’s works.
Could be false. The stimulus does not provide us any information about Clovio’s works to infer this statement. It is possible that Clovio’s style changed over time, so Clovio may not use the same features in all of his works.
E
There is an analyzable difference between Clovio’s contour and hatching styles and those of Michelangelo.
Must be true. We can infer that an analyzable difference exists because the analysis described in the stimulus did in fact help to show that some drawings formerly attributed to Michelangelo are actually by Clovio.
Summary
The electrification of musical instruments has enabled musicians to play at increased volume. Because individual musicians can play with increased volume, the average number of musicians per band has decreased. However, the number of musicians who play popular music professionally has increased because of electrification.
Strongly Supported Conclusions
Because of electrification of musical instruments, the total number of professional bands has increased.
A
The number of amateur musicians who play popular music has decreased.
This answer is unsupported. We don’t know anything about amateur musicians from the stimulus. The stimulus is limited to professional musicians.
B
Most professional musicians are able to play both electric and nonelectric instruments.
This answer is unsupported. We don’t know anything about nonelectric instruments from the stimulus. The stimulus is limited to electrified instruments.
C
The number of professional musicians in some bands has increased.
This answer is unsupported. The stimulus tells us that the average number of musicians per band has decreased.
D
The total number of professional bands has increased as a result of electrification.
This answer is strongly supported. If the average number of musicians per band decreased at the same time the total number of musicians increased, then it must be that the total number of bands has also increased.
E
Many professional musicians play in more than one band.
This answer is unsupported. We don’t know from the stimulus anything about the ability to play in more than one band.
Summarize Argument
The physician concludes that Jones did not swallow the chemical in question. As support, the physician references the following relationship:
Jones swallowed the chemical→mineral deficiency in blood→ skin inflammation
Jones’s skin was not inflamed, so the physician said that he did not swallow the chemical.
Jones swallowed the chemical→mineral deficiency in blood→ skin inflammation
Jones’s skin was not inflamed, so the physician said that he did not swallow the chemical.
Notable Assumptions
The physician assumes that there wouldn’t be any delay in the reactions. If there is any delay in the effects of either the chemical or the mineral deficiency, it could be the case that an insufficient amount of time had passed for Jones’s skin to become inflamed. If this is the case, Jones’s clear skin would be because not enough time had passed, not because he didn’t swallow the chemical.
A
Jones did not know that the chemical was dangerous.
The argument is based on the effects of consuming the chemical; these effects would occur regardless of whether Jones knew about the dangers.
B
Jones had suffered inflammation of the skin in the past.
We care about skin inflammation because it could be an indicator of whether or not Jones consumed the chemical; for the sake of the argument, we don’t care about skin inflammation that occurred independent of Jones’s potential consumption of the chemical.
C
It takes 48 hours for the chemical to bring about deficiency of the mineral in the blood.
This weakens the argument because it gives an alternate explanation for Jones’s clear skin. Jones’s skin could be clear because 48 hours hadn’t yet passed, not because he didn’t consume the chemical. Not enough time would have passed for the physician to make her conclusion.
D
Jones often worked with the chemical.
The argument is about whether or not Jones consumed the chemical in this specific instance; Jones’s history of working with the chemical is not relevant to the physician’s argument.
E
Deficiency in minerals other than the mineral in question can cause inflammation of the skin.
The physician’s argument is based on the fact that Jones’s skin is NOT inflamed, so other potential causes of skin inflammation are not relevant here.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that the melting of the ice contributed to the earthquakes in Sweden at the end of the last Ice Age. This is because melting ice reduced the weight pressing on the earth’s crust, which caused lasting cracks to form in the earth’s crust.
Notable Assumptions
The author assumes that cracks in the earth’s crust make earthquakes more likely to happen, or themselves constitute earthquakes. He also assumes that Sweden is situated in a location where the cracks caused by melting ice caused earthquakes.
A
The earth’s crust tends to crack whenever there is a sudden change in the pressures affecting it.
This more or less restates a premise. We need to strengthen the connection between the premises and the conclusion.
B
There are various areas in Northern Europe that show cracks in the earth’s crust.
The author never claims Sweden is the only place in Northern Europe where such earthquakes happened.
C
Evidence of severe earthquakes around the time of the end of the Ice Age can be found in parts of northern Canada.
While this strengthens the claim melting ice correlates with earthquakes, the author makes a causal claim. We want to strengthen the causation.
D
Severe earthquakes are generally caused by cracking of the earth’s crust near the earthquake site.
Cracks in the earth’s crust cause earthquakes. This strengthens the causal relationship that the author claims exists by clarifying how melting ice relates to earthquakes.
E
Asteroid impacts, which did occur at the end of the Ice Age, generally cause severe earthquakes.
This totally weakens the author’s argument. Asteroids, not melting ice, were responsible for the earthquakes.
Summary
A hummingbird’s egg accounts for 15 percent of an adult hummingbird’s weight. An adult goose is much larger than a hummingbird, but a goose’s egg accounts for only 4 percent of an adult goose’s weight. An adult ostrich is much larger than a goose, but ostrich eggs only account for 1.6 percent of an adult ostrich’s weight.
Strongly Supported Conclusions
The larger a bird species is, the smaller the ratio is between egg weight and the body weight of an adult bird.
A
The eggs of different bird species vary widely in their ratio of volume to weight.
This answer is unsupported. In the stimulus, we are comparing egg weight and volume to the weight and volume of an adult bird. This answer is comparing egg weight and volume of one species compared to the egg weight and volume of another.
B
The smaller and lighter the average adult members of a bird species are, the larger and heavier the eggs of that species are.
This answer is unsupported. From the stimulus, we only know that the ratio between the weight and volume of an egg increases the smaller the adult bird is. This doesn’t mean that the eggs are larger, just that they account for a bigger proportion of an adult’s weight.
C
The ratio of egg weight of a species to body weight of an adult member of that species is smaller for larger birds than for smaller ones.
This answer is strongly supported. This answer accurately captures the comparative difference of proportion between egg weight and volume of different bird species.
D
The size of birds’ eggs varies greatly from species to species but has little effect on the volume and weight of the adult bird.
This answer is unsupported. We don’t know from the stimulus anything about the size of any adult bird’s eggs. Rather, we only know something about the proportion of egg weight and volume compared to an adult bird.
E
Bird species vary more in egg size than they do in average body size and weight.
This answer is unsupported. We don’t know from the stimulus whether bird species vary in egg size at all. We only know that in different species of birds, egg weight and volume accounts for a different proportion of an adult bird’s weight.