3. In Asia, where palm trees are non-native, the trees’ flowers have traditionally been pollinated by hand, which has kept palm fruit productivity unnaturally low. When weevils known to be efficient pollinators of palm flowers were introduced into Asia in 1980, palm fruit productivity increased-by up to fifty percent in some areas-but then decreased sharply in 1984.
Which of the following statements, if true, would best explain the 1984 decrease in productivity?
A. Prices for palm fruit fell between 1980 and 1984 following the rise in production and a concurrent fall in demand.
B. Imported trees are often more productive than native trees because the imported ones have left behind their pests and diseases in their native lands.
C. Rapid increases in productivity tend to deplete trees of nutrients needed for the development of the fruit-producing female flowers.
D. The weevil population in Asia remained at approximately the same level between 1980 and 1984. C
E. Prior to 1980 another species of insect pollinated the Asian palm trees, but not as efficiently as the species of weevil that was introduced in 1980.
4. The tobacco industry is still profitable and projections are that it will remain so. In the United States this year, the total amount of tobacco sold by tobacco-farmers has increased, even though the number of adults who smoke has decreased.
Each of the following, if true, could explain the simultaneous increase in tobacco sales and decrease in the number of adults who smoke EXCEPT:
A. During this year, the number of women who have begun to smoke is greater than the number of men who have quit smoking
B. The number of teen-age children who have begun to smoke this year is greater than the number of adults who have quit smoking during the same period
C. During this year, the number of nonsmokers who have begun to use chewing tobacco or snuff is greater than the number of people who have quit smoking
D. The people who have continued to smoke consume more tobacco per person than they did in the past
E. More of the cigarettes made in the United States this year were exported to other countries than was the case last year.
新东方在线GMAT频道为大家带来GMAT逻辑笔记分享，希望对大家GMAT备考有所帮助。更多精彩尽请关注新东方在线GMAT频道! 一、 归纳题