LSAT-5-2-25,LSAT-5-2-20,LSAT-5-2-21

20.   In Brazil, side-by-side comparisons of Africanized honeybees and the native honeybees have shown that the Africanized bees are far superior honey producers. Therefore, there is no reason to fear that domestic commercial honey production will decline in the United States if local honeybees are displaced by Africanized honeybees.

Each of the following, if true, would weaken the argument EXCEPT:

(A) The honeybees native to Brazil are not of the same variety as those most frequently used in the commercial beekeeping industry in the United States.

(B) Commercial honey production is far more complicated and expensive with Africanized honeybees than it is with the more docile honeybees common in the United States.

(C) If Africanized honeybees replace local honeybees, certain types of ornamental trees will be less effectively pollinated.

(D) In the United States a significant proportion of the commercial honey supply comes from hobby beekeepers, many of whom are likely to abandon beekeeping with the influx of Africanized bees.（C）

(E) The area of Brazil where the comparative study was done is far better suited to the foraging habits of the Africanized honeybees than are most areas of the United States.

21.   The public is well aware that high blood cholesterol levels raise the risk of stroke caused by blood clots. But a recent report concludes that people with low blood cholesterol levels are at increased risk of the other lethal type of stroke—cerebral hemorrhage, caused when a brain artery bursts. The report suggests that because blood cholesterol plays a vital role in maintaining cell membranes, low blood cholesterol weakens artery walls, making them prone to rupture. The conclusion thus supports a long-standing contention by Japanese researchers that Western diets better protect against cerebral hemorrhage than do non-Western diets.

The argument is based on which one of the following assumptions?

(A) Western diets are healthier than non-Western diets.

(B) Western diets result in higher blood cholesterol levels than do non-Western diets.

(C) High blood cholesterol levels preclude the weakening of artery walls.

(D) Cerebral hemorrhages are more dangerous than strokes caused by blood clots.（B）

(E) People who have low blood pressure are at increased risk of cerebral hemorrhage.

这两道黄书上答案BC，ELSAT不同，ELSAT正确？