题目

A dropped bag of chips disturbed a cave ecosystem in Carlsbad Caverns National Park, New Mexico. This cave is almost cut off from the outside world, so introducing anything foreign can be harmful. "Things in the damp cave get wet quickly," says park guide Ashley The snack attracts tiny organisms, causing unwanted growth. Soon small animals like crickets and spiders eat, spreading the pollution. Rangers found the bag within hours. "But that can be all it takes," says Ashley, "I'm sure some crickets got a bit of the snack."Over 500 million people visit American public lands each year, creating many chances to harm wild places. "When you look at the numbers, it's incredible," says Watts, head of the Leave No Trace Center in Colorado, an organization aimed at minimizing human impact on nature.Food waste takes a long time to break down, especially in certain areas. "It takes much longer for an applet core to rot in a desert than in a forest." says Blye, a teacher at the University of Utah, Leaving waste introduces animals to an unnatural diet and changes their behavior with sometimes disastrous results. Bears who taste garbage and become a threat to humans may have to be put down. "Bears can get used to unnatural food in three weeks," says Watts. "Everyone loses in this case."Biological waste is also problematic. Dog waste brings new bacteria into the ecosystem and scares away deer. Meanwhile, human waste and toilet paper introduces dangerous bacteria into water sources.In national parks, trails (小路) are designed to avoid sensitive areas. Stepping off the trail, even for a quick photo, can scare wildlife away. Impacts from many visitors result in long-term damage to nature and wildlife. But people don't think of that when they see the perfect photo opportunity. "It's just such a hard thing to resist," says Blye. The risk to sensitive ecosystems isn't obvious. "It's easy to think, oh, there's wildflowers over there. I shouldn't step on that," says Blye, but these tiny ecosystems full of microscopic organisms essential to desert life provide many benefits, including reducing the risk of erosion (侵蚀) and helping absorb rainfall, and can take hundreds of years to return to its original state. （1） What attracted crickets and spiders? A . Foreign bacteria. B . Water sources. C . Food waste. D . Human trails. （2） What is the function of Ashley's quote underlined in paragraph 1? A . Describe cleanup process B . Emphasize instant damage C . Praise rangers' efficiency D . Explain cricket habits （3） Why does the writer mention wildflowers in paragraph 5? A . To praise their benefits to desert life. B . To highlight our damage to ecosystems. C . To stress their significance for photography. D . To show our unawareness of nature's sensitivity. （4） What is conveyed in this text? A . Encouraging wildlife protection. B . Leaving no trace in the wild. C . Promoting national park tourism. D . Restoring ecological damage. 答案： C B D B

查看本题答案和解析