标题: help!~~~another question from feifei80. thanks! [打印本页] 作者: justag 时间: 2003-1-3 07:24 标题: help!~~~another question from feifei80. thanks!
89. Rhizobium bacteria living in the roots of bean plants or other legumes produce fixed nitrogen, which is one of the essential plant nutrients and which for non-legume crops, such as wheat, normally must be supplied by applications of nitrogen-based fertilizer. So if biotechnology succeeds in producing wheat strains whose roots will play host to Rhizobium bacteria, the need for artificial fertilizers will be reduced.
The argument above makes which one of the following assumptions?
(A) Biotechnology should be directed toward producing plants that do not require artificial fertilize.
(B) Fixed nitrogen is currently the only soil nutrient that must be supplied by artificial fertilizer for growing wheat crops.
(C) There are no naturally occurring strains of wheat or other grasses that have Rhizobium bacteria living in their roots.
(D) Legumes are currently the only corps that produce their own supply of fixed nitrogen.
(E) Rhizobium bacteria living in the roots of wheat would produce fixed nitrogen.
the answer is E. but how do you guys eliminate B, since the difference betweeh the two terms "nitrogen-based fertilizer" and "artificial fertilizer" can't be ignored yah Thanks!
BTW: It's painful that I can't eliminate the fake choice from the two choices that are left. I often choose the wrong one of the two (( Are there any tips for me to utilize under this situation? Thanks a lot!作者: 回家过年 时间: 2003-1-3 10:27 标题: 咋的?
Thanks!