APP Currently, there is a widespread concern about the previously neglected connection between growing human population and decreasing wild species. As the two graphs obviously portrayed, American population in 1980 was 250 times than that in 1800, a trend accompanied by the extinction of nearly 70 kinds of wildlife in the past 300 years. A clear correlation is suggested that mankind has exer （共 1306 字） [阅读本文] >>
