Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that fairy circles are created by the burrowing activities of termites. This is based on the fact that sand termite colonires are found in every fairy circle that scientists have investigated.
Notable Assumptions
The author assumes that there’s no other explanation for the formation of fairy circles. For example, maybe fairy circles are produced by animals who eat the grass in a circular fashion? Or by other kinds of animals that burrow underground?
A
Dying grass plants within newly forming fairy circles are damaged only at the roots.
This strengthens by eliminating the possibility that fairy circles are formed by above-ground animals eating the grass. If the dying plants are damaged only at the roots, the cause is likely something underground.
B
The grasses that grow around fairy circles are able to survive even the harshest and most prolonged droughts in the region.
But why would circular patches without grass form? (B) doesn’t help establish that the cause is likely underground. It also doesn’t eliminate drought as an explanation for the circles, because drought isn’t something that would have created circles in the first place.
C
The soil in fairy circles typically has higher water content than the soil in areas immediately outside the circles.
If anything, this might weaken the argument by providing an alternate explanation for the formation of fairy circles — maybe it has something to do with the higher water content of the soil.
D
Fairy circles tend to form in areas that already have numerous other fairy circles.
This gives us information on where fairy circles tend to form. But this doesn’t suggest anything about the cause of fairy circles. Are they due to termites? Or something else?
E
Species of animals that feed on sand termites are often found living near fairy circles.
We already know from the premises that sand termites are found in every fairy circle investigated. We don’t need additional support for the presence of the termites near fairy circles. The issue is whether the termites that we know are there are the cause of fairy circles.
Extracurricular
Formation of Namibia’s fairy circles isn’t due to termites
Summary
Increasing an electrical load on a transmission line causes the line’s temperature to increase. Too big of a load causes the line to exceed its maximum operating temperature. However, the temperature is also affected with wind speed and direction. Strong winds cool the line more than light winds, and winds blowing across a line cools the line more than winds blowing parallel to it.
Strongly Supported Conclusions
When wind speed increases, the load a transmission line can carry without exceeding maximum operating temperature also increases.
A
Electrical utility companies typically increase the electrical load on their transmission lines on days on which the wind has a strong cooling effect.
This answer is unsupported. We don’t know how electrical utility companies usually operate. We can assume this is true, but we don’t know it for a fact based on the stimulus.
B
Transmission lines that run parallel to the prevailing winds can generally carry greater electrical loads than otherwise identical lines at a right angle to the prevailing winds.
This answer is anti-supported. Based on the stimulus, the winds blowing at a right angle would cool a line more than winds blowing parallel to the line.
C
The electrical load that a transmission line can carry without reaching its maximum operating temperature increases when the wind speed increases.
This answer is strongly supported. Load capacity is correlated with the temperature of a transmission line. The more external factors like wind cool the line, the greater load capacity the line has.
D
Air temperature has less effect on the temperature of a transmission line than wind speed does.
This answer is unsupported. We don’t know how the surrounding air temperature could effect a transmission line’s temperature.
E
The maximum operating temperature of a transmission line is greater on windy days than on calm days.
This answer is unsupported. We don’t know whether the maximum operating temperature for a transmission line ever changes.
Summarize Argument: Phenomenon-Hypothesis
The researcher hypothesizes that it’s because of primate biology—not just culture—that humans can tell whether a person is extroverted by looking at a picture of their neutral expression. Why? Because people can identify dominant chimpanzees by looking at similar pictures, and humans and chimpanzees are both primates.
Notable Assumptions
The researcher assumes only primate biology can explain this ability in humans, and not something else besides culture. She assumes abilities acquired through culture are not enough to allow humans to identify dominant chimpanzees through pictures of their neutral expressions. She also assumes humans have the ability to identify extroverted humans for the same reason they can identify dominant chimpanzees.
A
People are generally unable to judge the dominance of bonobos, which are also primates, by looking at pictures of them.
If anything, this weakens the researcher’s argument. It implies the ability to identify dominant individuals through pictures doesn’t extend to all primates—which suggests something other than primate biology is at play.
B
People are able to identify a wider range of personality traits from pictures of other people than from pictures of chimpanzees.
This is irrelevant. The researcher concludes primate biology allows humans to identify other extroverted humans—she makes no claim about other personality traits.
C
Extroversion in people and dominant behavior in chimpanzees are both indicators of a genetic predisposition to assertiveness.
This strengthens the researcher’s assumption that people are able to identify extroverted humans and dominant chimpanzees for the same reason. It implies humans in both cases are identifying genetically assertive individuals.
D
Any common ancestor of humans and chimpanzees would have to have lived over 7 million years ago.
This is irrelevant. It doesn’t change the fact that humans and chimpanzees are both primates, and the researcher credits primate biology—not a recent-ancestor relationship—for humans’ ability to identify extroverts.
E
Some of the pictures of people used in the experiments were composites of several different people.
If anything, this weakens the argument. It raises the possibility that humans aren’t actually that good at identifying extroverts among pictures of real people.
Summarize Argument: Counter-Position
The author proposes a different explanation for the origin of the ancient tracks on Malta. Some researchers think the tracks were intentionally cut to make it easier for carts to use them. The researchers’ evidence is that the track depth is all the same. The author acknowledges that the track depth is all the same, but thinks this just indicates the wheel diameter, which eroded the tracks to the same depth. The author’s theory that the uniform track depth indicates wheel diameter is used to support the idea that the network of tracks results from erosion from use by carts.
Identify Conclusion
The conclusion is the author’s explanation for the origin of the tracks: “The extensive network of ancient tracks on the island of Malta was most likely created through erosion caused by the passage of wheeled vehicles.”
A
The extensive network of ancient tracks on the island of Malta was most likely created through erosion caused by the passage of wheeled vehicles.
This is a verbatim restatement of the conclusion.
B
Some researchers have suggested that the ancient tracks on the island of Malta were in fact manually cut to facilitate the passage of carts.
This is the researchers’ view, which the author believes is likely wrong.
C
Some researchers cite the uniformity of the depth of the ancient tracks on the island of Malta to support the suggestion that they were manually cut.
This describes the support used by the researchers. The author reaches a different conclusion based on a different interpretation of that support.
D
The uniformity of depth of the ancient tracks on the island of Malta is probably indicative of the wheel diameter of the carts that passed over them.
This is an intermediate conclusion supported by the part after the colon. The author uses the theory that uniform track depth shows wheel diameter to help support the broader explanation that the tracks are caused by erosion from use by the carts.
E
The ancient tracks on the island of Malta were utilized until they eroded to a depth that made vehicle passage impossible.
This is a premise. It supports the intermediate conclusion that the uniform track depth shows wheel diameter. The theory that uniform track depth shows wheel diameter is used to support the broader explanation in the first sentence.
Summarize Argument
Ebsen’s recent ads were sent out to test whether they could influence popular opinion. This is supported by the premise that they were sent to too few households to actually influence popular opinion effectively. Furthermore, the campaign has been spending heavily to see whether the ads were effective.
Identify Conclusion
Ebsen’s recent ads were sent to test whether they could influence public opinion.
A
Normally, political candidates send out campaign material to influence popular opinion.
This is not the argument's main conclusion because it receives no support. This is context that introduces why campaign materials are normally sent out.
B
The recent ads for Ebsen’s campaign were sent to too few households to influence popular opinion effectively.
This is tricky, but it is not the main conclusion. It is a premise that supports the following sentence (main conclusion): The ads were sent out to test their ability to sway popular opinion. Furthermore, this receives no support and cannot be a conclusion.
C
The recent ads for Ebsen’s campaign were sent out to test their potential to influence popular opinion.
This accurately expresses the main conclusion of the argument. While campaign materials are normally sent out to influence opinion, these were sent to too few homes and were thus intended to test their potential to change public opinion.
D
The recent ads for Ebsen’s campaign covered a wide variety of topics.
This is a detail or fact in the argument, but it is not the conclusion because it does not receive any support.
E
Ebsen’s campaign has been spending heavily on follow-up surveys to gauge the ads’ effect on recipients.
This is a premise that supports the main conclusion that the ads were sent to test their potential to influence public opinion. This helps the argument because it shows that the campaign is interested to see how effective the ads were.