A. A.3), the chief concern of the scientists is ________. the impoverishment of developing countriesB. the explosion of the human populationC. the reduction of biological diversityD. the effect of global warming 参考答案:C 答案解析:[解析] 判断题。根据文章第三段,该段主要讨论了地球环境的变化(臭氧层被破坏以及全球气候变暖)对地球上丰富的生物资源的破坏。该段第一句指出:Many of the changes to Earth t