Some paleontologists believe that certain species of dinosaurs guarded their young in protective nests long after the young hatched. As evidence, they cite the discovery of fossilized hadrosaur babies and adolescents in carefully designed nests. But similar nests for hatchlings and adolescents are constructed by modern crocodiles, even though crocodiles guard their young only for a very brief time after they hatch. Hence, __________

Which one of the following most logically completes the argument?

For one academic year all the students at a high school were observed. The aim was to test the hypothesis that studying more increased a student’s chances of earning a higher grade. It turned out that the students who spent the most time studying did not earn grades as high as did many students who studied less. Nonetheless, the researchers concluded that the results of the observation supported the initial hypothesis.

Which one of the following, if true, most helps to explain why the researchers drew the conclusion described above?

Researchers had three groups of professional cyclists cycle for one hour at different levels of intensity. Members of groups A, B, and C cycled at rates that sustained, for an hour, pulses of about 60 percent, 70 percent, and 85 percent, respectively, of the recommended maximum pulse rate for recreational cyclists. Most members of Group A reported being less depressed and angry afterward. Most members of Group B did not report these benefits. Most members of Group C reported feeling worse in these respects than before the exercise.

Which one of the following is most strongly supported by the information above?

A mass of “black water” containing noxious organic material swept through Laurel Bay last year. Some scientists believe that this event was a naturally occurring but infrequent phenomenon. The black water completely wiped out five species of coral in the bay, including mounds of coral that were more than two centuries old. Therefore, even if this black water phenomenon has struck the bay before, it did not reach last year’s intensity at any time in the past two centuries.

Which one of the following is an assumption required by the argument?

The Iliad and the Odyssey were both attributed to Homer in ancient times. But these two poems differ greatly in tone and vocabulary and in certain details of the fictional world they depict. So they are almost certainly not the work of the same poet.

Which one of the following statements, if true, most weakens the reasoning above?

In response to several bacterial infections traced to its apple juice, McElligott now flash pasteurizes its apple juice by quickly heating and immediately re-chilling it. Intensive pasteurization, in which juice is heated for an hour, eliminates bacteria more effectively than does any other method, but is likely to destroy the original flavor. However, because McElligott’s citrus juices have not been linked to any bacterial infections, they remain unpasteurized.

The statements above, if true, provide the most support for which one of the following claims?

Sociologist: Widespread acceptance of the idea that individuals are incapable of looking after their own welfare is injurious to a democracy. So legislators who value democracy should not propose any law prohibiting behavior that is not harmful to anyone besides the person engaging in it. After all, the assumptions that appear to guide legislators will often become widely accepted.

The sociologist’s argument requires the assumption that

No matter how conscientious they are, historians always have biases that affect their work. Hence, rather than trying to interpret historical events, historians should instead interpret what the people who participated in historical events thought about those events.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument fails to consider the possibility that

Humanitarian considerations aside, sheer economics dictates that country X should institute, as country Y has done, a nationwide system of air and ground transportation for conveying seriously injured persons to specialized trauma centers. Timely access to the kind of medical care that only specialized centers can provide could save the lives of many people. The earnings of these people would result in a substantial increase in country X’s gross national product, and the taxes paid on those earnings would substantially augment government revenues.

The argument depends on the assumption that

It has been suggested that a television set should be thought of as nothing more than “a toaster with pictures” and that since we let market forces determine the design of kitchen appliances we can let them determine what is seen on television. But that approach is too simple. Some governmental control is needed, since television is so important politically and culturally. It is a major source of commercial entertainment. It plays an important political role because it is the primary medium through which many voters obtain information about current affairs. It is a significant cultural force in that in the average home it is on for more than five hours a day.

Which one of the following most accurately expresses the role played in the argument by the claim that television is so important politically and culturally?

In a study, one group of volunteers was fed a high-protein, low-carbohydrate diet; another group was fed a low-protein, high-carbohydrate diet. Both diets contained the same number of calories, and each volunteer’s diet prior to the experiment had contained moderate levels of proteins and carbohydrates. After ten days, those on the low-carbohydrate diet had lost more weight than those on the high-carbohydrate diet. Thus, the most effective way to lose body fat is to eat much protein and shun carbohydrates.

Which one of the following, if true, most weakens the argument above?

The average length of stay for patients at Edgewater Hospital is four days, compared to six days at University Hospital. Since studies show that recovery rates at the two hospitals are similar for patients with similar illnesses, University Hospital could decrease its average length of stay without affecting quality of care.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument