Biological diversity has never been so threatened as it is today as a result of the process of human civilization. The various forms of pressure created by human activity have destroyed natural balance, led to the deterioration of natural habitats, genetic erosion and the rarity, even disappearance, of a number of plant and animal species.
As the pace of civilization accelerates, more people, taking more space, needing to use more natural resources, engaging in ever-growing consumption, impose severe deterioration on the habitat of animals. An increasing number of people come to realize that the disappearance of animals will result in serious threat to the equilibrium of ecosystem. Simply put, the extinction of hawks, a rat-eating bird seen in many regions, will result in the rapid propagation of rats. And rats, further, will destroy the prairies and threaten the other animals like gazelles, zebras and others, who live on grass and green lands. The coexistence of animals and human beings creates perfect harmony and brings about the vividness to our planet.
It is hard to imagine what our world would be like without animals. Sociologists also point out that the disappearance of animals can cause social and economic problems. Animal trade, as a supporting sector to the world economy, was very active before. However, the situation is beyond control since animal trade is very profitable and alluring. Many species cannot escape the adversity of being killed.
Certainly, our diet cannot be without meat. There are living stocks, which can provide us with sufficient and nutritious produce. Therefore, we need not to resort to wild animals, especially the endangered ones. To protect animals is to protect our living environment. Every individual should join efforts to keep the diversity of animals.
专四考前恶补:语法词汇(6)
2014年专业英语四级高频词汇统计:犯罪资讯
英语专业四级语法词汇辅导:be+不定式结构
英语专业四级考试必备高频短语集锦(7)
英语专业四级考试必备高频短语集锦(9)
专四考前恶补:语法词汇(8)
年英语专业四级考试语法词汇强化练习题(1)
专四考前恶补:语法词汇(15)
英语专业四级考试语法词汇强化练习题(5)
英语专业四级考试必备高频短语集锦(4)
英语专业四级词汇与语法全真模拟练习48
英语专业四级语法词汇辅导:关于dare的意义和用法
专四考前恶补:语法词汇(22)
英语专业四级语法词汇辅导:定语从句中关系代词that的用法
英语专业四级考试必备高频短语集锦(2)
英语专业四级词汇与语法全真模拟练习68
专四考前恶补:语法词汇(21)
英语专业四级考试必备高频短语集锦(11)
专四考前恶补:语法词汇(7)
英语专业四级考试必备高频短语集锦(5)
英语专业四级考试必备高频短语集锦(3)
英语专业四级考试语法词汇练习题及答案(9)
英语专业四级考试语法词汇强化练习题(2)
英语专业四级考试必备高频短语集锦(10)
专四考前恶补:语法词汇(17)
专四考前恶补:语法词汇(11)
英语专业四级词汇与语法全真模拟练习67
英语专业四级考试必备高频短语集锦(1)
英语专业四级考试必备高频短语集锦(14)
专四考前恶补:语法词汇(9)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |