凌乱了~~~CR一个~~~help~~~

piaoface

In parts of South America, vitamin-A deficiency is a serious health problem, especially among children.In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A. The plan has good chances of success, since sweet potato is a staple of the region’s diet and agriculture, and the varietiescurrently grown contain little beta-carotene.

Which of the following, if true, most strongly supports the prediction that the plan will succeed?

A. There are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.

B. The flesh of SPK004 differs from that of the currently cultivated sweet potatoes in color and texture, so traditional foods would look somewhat different when prepared from SPK004.

C. For successful cultivation of SPK004, a soil significantly richer in nitrogen is needed than is needed for the varieties of sweet potato currently cultivated in the region.

D. There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.

E. The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.

这个题目，我不懂为什么选E，不选D? 求解答~~~~

cdwayne

In parts of South America, vitamin-A deficiency is a serious health problem, especially among children.In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A. The plan has good chances of success, since sweet potato is a staple of the region's diet and agriculture, and the varietiescurrently grown contain little beta-carotene.

Which of the following, if true, most strongly supports the prediction that the plan will succeed?

A. There are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.

B. The flesh of SPK004 differs from that of the currently cultivated sweet potatoes in color and texture, so traditional foods would look somewhat different when prepared from SPK004.

C. For successful cultivation of SPK004, a soil significantly richer in nitrogen is needed than is needed for the varieties of sweet potato currently cultivated in the region.

D. There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.

E. The currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.

這個題目，我不懂為什麼選E，不選D? 求解答~~~~

-- by 會員 piaoface (2011/9/21 23:05:25)

core: A Vitamin-A deficiency happens, SPK004, which is rich in beta carotene solves this problem.
(D) SPK004 is not necessarily to be the best solution. (夠用就好)
(E) It states that the solution improves the deficiency issue without losing other important nutrients. (不要挖東牆補西牆)

mntmnt123

unless an argument specifically compares a course of action to other courses of action, and/or states that a course of action is best/worst/optimal/etc., then other courses of action are irrelevant.