Pesticide has made a great contribu tion on controlling plant diseases and insect pests,however it also contaminated ecological environment and threatened the secu rity of birds.

 
  • 农药曾经为人类控制生物病虫害作出过巨大贡献,但是农药污染也破坏了生态环境,对野生鸟类的生存造成了严重威胁。
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