新理念綜合教程book4單元測試-文庫吧
2025-07-21 08:06 本頁面
【正文】 but it is important to recognize the significance of biological diversity in all ecosystems. As the human population continues to expand, it will negatively affect one after another of Earth39。s ecosystems. In terrestrial ecosystems and in fringe marine ecosystems (such as wetlands), the most mon problem is habitat destruction. In most situations, the result is irreversible. Now humans are beginning to destroy marine ecosystems through other types of activities, such as the disposal and runoff of poisonous waste。 in less than two centuries, by significantly reducing the variety of species on Earth, they have unraveled cons of evolution and irrevocably redirected its course.Certainly, there have been periods in Earth39。s history when mass extinctions have occurred. The extinction of the dinosaurs was caused by some physical event, either climatic or cosmic. There have also been less dramatic extinctions, as when natural petition between species reached an extreme conclusion. Only percent of the species that have lived on Earth have survived to the present, and it was largely chance that determined which species survived and which died out.However, nothing has ever equaled the magnitude and speed with which the human species is altering the physical and chemical world and demolishing the environment. In fact, there is wide agreement that it is the rate of change humans are inflicting, even more than the changes themselves, that will lead to biological devastation. Life on Earth has continually been in flux as slow physical and chemical changes have occurred on Earth, but life needs time to adapt — time for migration and genetic adaptation within existing species and time for the proliferation of new genetic material and new species that may be able to survive in new environments. 26. Which is the best title of the passage?A. The Variety of SpeciesB. The Rapid Destruction of the Tropical Rain ForestC. Species39。 Adaptation to New EnvironmentD. The Impact of Human Activities on Earth39。s Ecosystems請根據(jù)需要填入Script：正正確答案：D得分：2分27. According to the passage,
范文總結相關推薦
鄂ICP備17016276號-1