[单项选择]

In his 1979 book, The Sinking Ark, biologist Norman Myers estimated that (1) of more than 100 human-caused extinctions occur each clay, and that one million species (2) by the century’s end. Yet there is little evidence of (3) that number of extinctions. For example, only seven species on the (4) species list have become extinct (5) the list was created in 1973.
Bio- (6) is an important value, according to many scientists. Nevertheless, the supposed mass extinction rates bandied about are (7) by multiplying (8) by improbables to get imponderables.
Many estimates, for instance, rely a great deal on a "species-area (9) ", which predicts that twice as many species will be found on 100 square miles (10) on ten square miles. The problem is that species are not distributed (11) , so bow much of a forest are destroyed may be as important as (12) .
(1
A. underplay
B. underrate
C. understate
D. undermine

最新试题

• ●    G1P0，孕38周，基层转诊。腹部检查：子宫横椭圆形，儿头位于右侧腹，胎心于右脐旁可闻及，136次／
• ●    [单选题]’年2月，公安部印发了《关于全国公安机关坚持发展新时代“枫桥经验”的意见》，进一步部署推动
• ●    计划的三要素不正确的是（　）
• ●    [多选题] 正当防卫与紧急避险的相同之处是( ).
• ●    35岁女性，下唇溃烂、出血、疼痛6个月。查体：下唇唇红黏膜中份可见直径0.8cm左右的糜烂区，覆盖血
• ●    [判断题]高倍泡沫发生器产生的泡沫倍数较高，使用时可在受灾空间的下方灌填，或者由通道向远距离输送