New evidence suggests that the collapse of Egypt’s old kingdom some 4,000 years ago was caused by environmental catastrophe rather than internal social upheaval. Ocean sediments reveal a period of global cooling at the time, a condition generally associated with extended droughts. There were, no doubt, serious social problems in Egypt at the time, but they resulted from a severe dry spell.

Which one of the following, if true, would most strengthen the argument?

The number of applications for admission reported by North American Ph.D. programs in art history has declined in each of the last four years. We can conclude from this that interest among recent North American college and university graduates in choosing art history as a career has declined in the last four years.

Each of the following, if true, weakens the argument EXCEPT:

Some scientists believe that 65 million years ago an asteroid struck what is now the Yucatan Peninsula, thereby causing extinction of the dinosaurs. These scientists have established that such a strike could have hurled enough debris into the atmosphere to block sunlight and cool the atmosphere. Without adequate sunlight, food sources for herbivorous dinosaurs would have disappeared, and no dinosaurs could have survived a prolonged period of low temperatures. These same scientists, however, have also established that most debris launched by the asteroid would have settled to the ground within six months, too soon for the plants to disappear or the dinosaurs to freeze.

Which one of the following, if true, most helps to resolve the apparent discrepancy between the scientists’ beliefs and the scientists’ results, as described above?

Some teachers claim that students would not learn curricular content without the incentive of grades. But students with intense interest in the material would learn it without this incentive, while the behavior of students lacking all interest in the material is unaffected by such an incentive. The incentive of grades, therefore, serves no essential academic purpose.

The reasoning in the argument is flawed because the argument

Economist: Technology now changes so rapidly that workers need periodic retraining. Such retraining can be efficient only if it allows individual companies to meet their own short-term needs. Hence, large governmental job retraining programs are no longer a viable option in the effort to retrain workers efficiently.

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

Recent research indicates that increased consumption of fruits and vegetables by middle-aged people reduces their susceptibility to stroke in later years. The researchers speculate that this may be because fruits and vegetables are rich in folic acid. Low levels of folic acid are associated with high levels of homocysteine, an amino acid that contributes to blocked arteries.

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

Thirty years ago, the percentage of the British people who vacationed in foreign countries was very small compared with the large percentage of the British population who travel abroad for vacations now. Foreign travel is, and always has been, expensive from Britain. Therefore, British people must have, on average, more money to spend on vacations now than they did 30 years ago.

The argument requires assuming which one of the following?

Mystery stories often feature a brilliant detective and the detective’s dull companion. Clues are presented in the story, and the companion wrongly infers an inaccurate solution to the mystery using the same clues that the detective uses to deduce the correct solution. Thus, the author’s strategy of including the dull companion gives readers a chance to solve the mystery while also diverting them from the correct solution.

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

Sociologist: The more technologically advanced a society is, the more marked its members’ resistance to technological innovations. This is not surprising, because the more technologically advanced a society is, the more aware its members are of technology’s drawbacks. Specifically, people realize that sophisticated technologies deeply affect the quality of human relations.

The claim that the more technologically advanced a society is, the more aware its members are of technology’s drawbacks plays which one of the following roles in the sociologist’s argument?

One-year-olds ordinarily prefer the taste of sweet food to that of salty food. Yet if one feeds a one-year-old salty food rather than sweet food, then over a period of about a year he or she will develop a taste for the salty flavor and choose to eat salty food rather than sweet food. Thus, a young child’s taste preferences can be affected by the type of food he or she has been exposed to.

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

Consumers are deeply concerned about the quantity of plastic packaging on the market and have spurred manufacturers to find ways to recycle plastic materials. Despite their efforts, however, only 6.5 percent of plastic is now being recycled, as compared to 33 percent of container glass.

Each of the following, if true, helps to explain the relatively low rate of plastic recycling EXCEPT:

Environmentalist: The complex ecosystem of the North American prairie has largely been destroyed to produce cattle feed. But the prairie ecosystem once supported 30 to 70 million bison, whereas North American agriculture now supports about 50 million cattle. Since bison yield as much meat as cattle, and the natural prairie required neither pesticides, machinery, nor government subsidies, returning as much land as possible to an uncultivated state could restore biodiversity without a major decrease in meat production.

Which one of the following most accurately expresses the environmentalist’s main conclusion?