The plant called the scarlet gilia can have either red or white flowers. It had long been
A. Uncovered scarlet gilia flowers, whether red or white, became pollinated at approximately equal rates.
B. Some red flowers of the scarlet gilia that remained uncovered at all times never became pollinated.
C. White flowers of the scarlet gilia that were covered at night became pollinated with greater frequency than white flowers of the scarlet gilia that were left uncovered.
D. Scarlet gilia plants with red flowers covered by day and scarlet gilia plants with white flowers covered at night remained unpollinated.
E. In late August, when most of the hummingbirds had migrated but hawkmoths were still plentiful, red scarlet gilia plants produced fruit more frequently than they had earlier in the season.
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Many geologists theorize that the trail of volcanic craters and cinder cones along the Snake River plain of southern Idaho was produced as the North American continent slid westward over a stationary " plume," a vertical channel through which molten rock rose intermittently from the Earth s core to burst through its crust. Which of the following, if true, tends to support the geologists theory of how the trail was produced？
A. The largest craters and cinder cones are on the eastern margin of the trail.
B. The most violent volcanic activity apparently occurred at the western margin of the trail.
C. The craters and cinder cones are evenly spaced throughout the extent of the trail.
D. The newest craters and cinder cones are on the eastern margin of the trail.
E. The craters and cinder cones on the western margin of the trail generally took longer to form. than did those on the eastern margin.
In recent years shrimp harvests of commercial fishermen in the South Atlantic have declined dramatically in total weight. The decline is due primarily to competition from a growing number of recreational fishermen, who are able to net young shrimp in the estuaries where they mature. Which of the following regulatory actions would be most likely to help increase the shrimp harvests of commercial fishermen？
A. Requiring commercial fishermen to fish in estuaries.
B. Limiting the total number of excursions per season for commercial fishermen.
C. Requiring recreational fishermen to use large-mesh nets in their fishing.
D. Putting an upper limit on the size of the shrimp recreational fishermen are allowed to catch.
E. Allowing recreational fishermen to move out of estuaries into the South Atlantic.
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.
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.
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