求助~狒狒第89题

helluft

89. Rhizobium bacteria living in the rootsof bean plants or other legumes produce fixed nitrogen, which is one of theessential plant nutrients and which for non-legume crops, such as wheat,normally must be supplied by applications of nitrogen-based fertilizer. So ifbiotechnology succeeds in producing wheat strains whose roots will play host toRhizobium bacteria, the need for artificial fertilizers will be reduced.

The argument above makes which one of thefollowing assumptions?

(A) Biotechnology should be directed towardproducing plants that do not require artificial fertilize.

(B) Fixed nitrogen is currently the onlysoil nutrient that must be supplied by artificial fertilizer for growing wheatcrops.

(C) There are no naturally occurringstrains of wheat or other grasses that have Rhizobium bacteria living in theirroots.

(D) Legumes are currently the only corpsthat produce their own supply of fixed nitrogen.

(E) Rhizobium bacteria living in the rootsof wheat would produce fixed nitrogen.

答案给的是E，但是根据Rhizobium bacteria 在根部能产生固氮->人工肥料可以减少使用这个逻辑，为什么B不是assumption之一呢。

如果出了固氮外人工化肥还提供别的营养，那即使固氮可以通过自己生成，人工化肥还是不能少啊

请大牛指教

alzn2765

类比推理找假设

前提： Rhizobium bacteria living in the roots of bean plants or other legumes produce fixed nitrogen, which is one of theessential plant nutrients and which for non-legume crops, such as wheat,normally must be supplied by applications of nitrogen-based fertilize
结论： if biotechnology succeeds in producing wheat strains whose roots will play host to Rhizobium bacteria, the need for artificial fertilizers will be reduced

结论要成立，则bean和wheat在“Rhizobium bacteria生长在其根部产生氮化物”必须属性一致，才有可比性。
前提和结论之间有一个gap: 在roots of bean plants or other legume produce fixed nitrogen的Rhizobium bacteria，必须在wheat strain roots上做同样的事，否则结论不会成立。

E就是补充了这个“断桥”。

(B) Fixed nitrogen is currently the only soil nutrient that must be supplied by artificial fertilizer for growing wheatcrops. 请找出only在文中的出处。而且B无法填补前提和结论之间的gap。

如果出了固氮外人工化肥还提供别的营养，那即使固氮可以通过自己生成，人工化肥还是不能少啊
只要固氮可以通过自己生成，至少氮肥不用了，是不是导致了the need for artificial fertilizers will be reduced了？没说全都不用啊，只需要reduce。