环境(Environment)
Like all other living beings, humans have clearly changed their environment, but they have done so generally on a grander scale than have other species. Some of these changes-such as the destruction of the world's tropical rain forests to create grazing land for cattle or the drying up of almost three-quarters of the Aral Sea, once the world's fourth-largest freshwater lake, for irrigation purposes-have led to altered climate patterns, which in turn have changed the distribution of species of animals and plants.
Scientists are working to understand the long-term
consequences that human actions have on ecosystems, while environmentalists-professionals in various fields, as well as
concerned citizens in the United States and other countries-are struggling to lessen the impact of human activity on the natural world.
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