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题库 / Prep2012-CR-30
In preparation for a large-scale tree-planting project, Thomasville has recorded the location, species, and condition of every tree in its downtown area. The results will be compared with results of the last such tree census, taken 20 years ago. Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now.
Which of the following, if true, most seriously undermines the claim that the tree-planting proposal will assure an abundant tree population?
Because of strict laws governing industrial development, environmental conditions in Thomasville are unlikely to become harsher for trees than they have been during the last 20 years.
Thomasville has reliable records to show which trees in existence 20 years ago were cut down to permit new construction downtown.
A number of trees from one of the species widespread in Thomasville 20 years ago reached the end of their natural life span in the intervening period.
Very few species of trees grow as well in urban conditions as in natural conditions.
A city with a high proportion of any one species of trees can have its tree population devastated by one outbreak of a disease.
方案： 选出存活率记录最好的树
目标：带来丰富的tree population
反驳;有副作用；不可行，达不到目标 提方案的CE
再排除 C：20年前长的好的树是记录最好的树？现在要死了和目标的关系？无关
E 任何单一树会被疾病减少数量 方案有缺陷
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