1. After the national speed limit of 55 miles per hour was imposed in 1974, the number of deaths per mile driven on a highway fell abruptly as a result. Since then, however, the average speed of vehicles on highways has risen, but the number of deaths per mile driven on a highway has continued to fall.
Which of the following conclusions can be properly drawn from the statements above?
(A) The speed limit alone is probably not responsible for the continued reduction in highway deaths in the years after 1974.
(B) People have been driving less since 1974.
(C) Driver-education courses have been more effective since 1974 in teaching drivers to drive safely.
(D) In recent years highway patrols have been less effective in catching drivers who speed.(A)
(E) The change in the speed limit cannot be responsible for the abrupt decline in highway deaths in 1974.
2. Neighboring landholders: Air pollution from the giant aluminum refinery that has been built next to our land is killing our plants.
Company spokesperson: The refinery is not to blame, since our study shows that the damage is due to insects and fungi.
Which of the following, if true, most seriously weakens the conclusion drawn by the company spokesperson?
(A) The study did not measure the quantity of pollutants emitted into the surrounding air by the aluminum refinery.
(B) The neighboring landholders have made no change in the way they take care of their plants.
(C) Air pollution from the refinery has changed the chemical balance in the plants’ environment, allowing the harmful insects and fungi to thrive.
(D) Pollutants that are invisible and odorless are emitted into the surrounding air by the refinery.(C)
(E) The various species of insects and fungi mentioned in the study have been occasionally found in the locality during the past hundred years....…………
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