题型:阅读理解 题类:常考题 难易度:普通
山西省祁县中学2017-2018学年高一上学期英语12月月考试卷
Scientists have found living organisms(有机体) that could be 50,000 years old recently. The organisms were found in a hot, but beautiful cave system in Naica, Mexico. These ancient life forms can be seen only with a microscope, which proves they are probably microbes(微生物).
Penelope Boston leads the Astrobiology Institute at NASA, the space agency of the United States. These ancient organisms are able to exist by eating minerals such as iron and manganese. If the findings are confirmed, they will show how microbes can survive in extreme conditions.
Researchers have been studying ancient microbes for nine years. Forty different kinds of microbes and some viruses were found in the underground area this time. The genetic(基因的) structures of these organisms are different from those of their nearest relatives –viruses. That is similar to that humans are genetically different from mushrooms growing in forest. The caves in Naica are 800 kilometers deep. Before the miners began working in the caves, the area was isolated from the surface and the outside world.
Some of the caves are as big as the large religious centers built during Europe's Middle Ages. There are crystals(晶体) covering the walls. Scientists must wear special clothing to keep cool. And the clothing keeps the crystals safe from human germs or other damage. The researchers could only work for about 20 minutes at a time before they have to go to a room that is 28 degrees Celsius to cool down.
NASA officials would not let Boston share her findings with scientific experts until the last week's announcement. So scientists could not say much about the findings. But Norine Noonan, a biologist at the University of South Florida, said she believed them. “Why are we surprised?” Noonan asked, “As a biologist, I would say life on Earth is extremely tough and versatile.” “What's more, these organisms are not the oldest life forms on Earth. Scientists published studies about living microbes that may be 500,000 years old several years ago,” she added.
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