Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle. Which of the following statements, if true, would most strengthen the scientists hypothesis？
A. The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees.
Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were critical breeding areas for the native species of fish.
C. The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas the lowest recorded temperature of the river after the dam was built has been 43 degrees.
D. Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing with the declining native fish species for food and space.
E. Five of the fish species native to the Emerald River are not native to any other river in North America.
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A research study reports that a particular educational program has improved the prospects
A. The parents of preschool children in the United States are attracted to educational fads and do not have a clear idea of what sorts of early education programs might benefit their children.
B. The cognitive abilities of children are constantly changing between ages three and five.
C. The researchers unwittingly included a substantial number of children who had been previously exposed to another educational enrichment program.
D. Many parents erroneously presume that early formal instruction takes up time that children could better spend exploring their worlds independently.
E. It would require extraordinary public expense to establish such educational enrichment programs on a national basis.
Advertisers are often criticized for their unscrupulous manipulation of peoples tastes and
A. The advertisers switched their advertisements to other family newspapers.
B. Some advertisers switched from family newspapers to advertise in the changed publication.
C. The advertisers expected their product sales to increase if they stayed with the changed publication, but to decrease if they withdrew.
D. People who generally read family newspapers are not likely to buy newspapers that concentrate on sex and violence .
E. It was expected that the changed publication would appeal principally to those in a different income group.
Which of the following, if true, would provide most support for concluding from the survey
A. Changes in the level of drug use by high school seniors are seldom matched by changes in the level of drug use by other people below the age of 20.
B. In the past, high school seniors were consistently the population group most likely to use illegal drugs and most likely to use them heavily.
C. The percentage of high school seniors who use illegal drugs is consistently very similar to the percentage of all people below the age of 20 who use illegal drugs.
D. The decline revealed by the surveys is the result of drug education programs specifically targeted at those below the age of 20.
E. The number of those surveyed who admit to having sold illegal drugs has declined even faster than has the number who have used drugs.
In Argonia the average rate drivers pay for car accident insurance is regulated to allow insurance companies to make a reasonable profit. Under the regulations, the rate any individual driver pays never depends on the actual distance driven by that driver each year. Therefore, Argonians who drive less than average partially subsidize the insurance of those who drive more than average. The conclusion above would be properly drawn if it were also true that in Argonia
A. the average accident insurance rate for all drivers rises whenever a substantial number of new drivers buy insurance.
B. the average cost to insurance companies of insuring drivers who drive less than the annual average is less than the average cost of insuring drivers who drive more than the annual average.
C. the lower the age of a driver, the higher the insurance rate paid by that driver.
D. insurance company profits would rise substantially if drivers were classified in terms of the actual number of miles they drive each year.
E. drivers who have caused insurance companies to pay costly claims generally pay insurance rates that are equal to or lower than those paid by other drivers.
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