(单词翻译:单击)
Fresh water Rivers, lakes and wet-lands are sources of fresh water,not only for humans, but for wildlife too. Due to pollution and climate change, about 50% of the world's fresh water habitats have been destroyed in the last 100 years.And more than 3 billion people in poor countries do not have enough clean water. The WWF works hard to protect fresh-water environment from pollution and to help people in developing countries have access to safe, clean water.Nobody knows exactly how many species of plants and animals there are on Earth. Scientists say that there would be as many as 15 million different species.Sadly, many species have become extinct and many are in danger of extinction. But thanks to the hard work of organizations like the WWF, more and more have a chance to survive.
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