Reading Comprehension
从下列每篇短文的问题后所给的四个选择项中选出一个最佳答案。 

Endangered Species（濒危物种）

     Ever since life on earth began, animals and plants have died out and new ones have appeared. Long ago, most animals and plants died out because of natural events, like earthquakes or climatic changes. Today, plants and animals are in danger mostly because of human beings.

     Man has been killing animals and gathering plants for food, medicine, clothes and shelters. For centuries, tigers and other wild animals have been killed for their skins; whales have been hunted because of their oil and fat.

     More and more people live in our world. They need more space to live in. Rain forests, grasslands and other parts of nature are destroyed and people start to settle there. They take away the natural home of plants and animals. This causes the disappearance of many species. Now the most endangered areas are the tropical rain forests. More than 50％ of all animals and plants live there. Every day, large areas of rain forest are destroyed and many species die out.

     Moreover, man’s other activities can also kill off some species. Waste water from factories goes into rivers and lakes and can poison fish there. Species like wolves have been killed by humans because they are seen as a danger to farm animals. Sometimes native animals become endangered when a new species comes to live in a place. Foxes, the natural enemy of rabbits, were brought to Australia to kill off rabbits. But they killed kangaroos（袋鼠）there instead.

     People have hurt plants and animals but they also want to protect them. All over the world organizations like the World Wildlife Fund （WWF） are helping to protect endangered plants and animals. They collect money for their projects and make governments and the public listen to them. New laws have also been made to protect endangered plants and animals all over the world.