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  3. A new type of organism discovered in an Arctic tunnel came to life in the l

A new type of organism discovered in an Arctic tunnel came to life in the l

游客2023-11-07  30
问题      A new type of organism discovered in an Arctic tunnel came to life in the lab after being frozen for 32,000 years. The deep-freeze bacteria could point to new methods of cryogenics, and they are the sort of biology scientists say might exist on Mars and other planets and moons. "The existence of microorganisms in these harsh environments suggests——but does not promise——that we might one day discover similar life forms in the glaciers or permafrost of Mars or in the ice crust and oceans of Jupiter’s moon Europa," said Richard Hoover, an astrobiologist at NASA’s Marshall Space Flight Center. Other microbes have been discovered in similar frigid environments, sometimes clinging to pockets of liquid water in ice packs. And some microbes survive in ice as spores, but they need to be cultured to bring them to life.
     The announcement of the discovery Wednesday comes just a day after a team of European re- searchers said they found blocks of ice just under the surface of Mars near the equator. The Europeans said the ice, between 2 million and 5 million years old, could serve as storehouses for life. The new bacterium thrives under a microscope despite having been thawed from ice dating back some 32,000 years, to the Pleistocene era. Living bacteria are stained green.
     Hoover said the creatures he has found might be able to survive in their suspended state for millions of years. The discovery opens up a whole new possibility that a future mission to Mars might be able to retrieve any life that’s there. "Ice samples from this [Martian ice] sea could con-rain cryopreserved microorganisms if life ever flourished on the surface of Mars," Hoover said in a telephone interview. He is particularly excited about the instant revival qualities of the creatures found in Alaska. "You might actually get them growing in pure culture," he said of the potential Martian cousins. It would be a "wonderful way of retrieving intact, viable Martian organisms, if they are there."
     Water does not guarantee life, but it is a crucial ingredient. Hoover said the Martian ice blocks are so near the surface that they might partly melt in summer, creating underground pools of water that would allow any microorganisms to grow and reproduce. (Life above ground is considered unlikely due to Mars’ dry surface conditions and intense radiation. ) [br] The best title for the passage might be _________.
选项 A、Life Possibility on Mars.
B、Creatures Frozen 320,000 years Still Alive.
C、Growth of Microorganisms.
D、New Scientific Discovery.
答案 B
解析 主旨题。文章主要讨论了在北冰洋地坑中发现的新生物种类竟然在320，000年之后复活这件事情及其引发的科学家和研究人员对别的星球是否有生命存在的种种猜想．选项B相比较而言是最具概括性的，所以是正确答案。
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