[Gardener wanted.NASA requires a gardener to grow plants in a greenhouse.The successful applicant must be willing to travel long

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问题         [Gardener wanted.NASA requires a gardener to grow plants in a greenhouse.The successful applicant must be willing to travel long distances.The location is Mars.Transport will be provided.Please contact for further details and to arrange an interview.]

       For the moment the position described above is an imaginary vacancy.It will probably be many more years before gardeners are needed on Mars.However, the actual growing of plants on Mars may be only a year away.Scientists are currently suggesting a mission that might put plants on Mars next year.
       The idea is to use a small NASA spacecraft called a ’Mar Scout’ to send the plants in a miniature greenhouse.Landing on Mars it would scoop up some Martian soil.Enhance it with nutrients and then try to germinate and grow the seeds.The seeds would be bioengineered mustard plants, altered so that they would glow when they are struggling.Using bioengineering the mustard seed genes can be combined with jellyfish genes that make the plants glow with a soft green aura when they encounter problems.Healthy, thriving plants will not glow.When the scientists observe a plant is glowing, they can study it and learn what needs to be charged for plants to be able lo grow on Mars.
       The aim of the experiment is to eventually be able to successfully grow plants in Martian greenhouses, and perhaps one day openly on Mars itself.What value does this have? After all, it would not be viable to farm food on Mars and then return it to Earth.
       The meaning lies in being able to sustain life on Mars itself.It is far too expensive to transport all the supplies that would be needed by a Martian colony form Earth.So a crucial element for establishing a long-term human presence on Mars is a sustainable life support system.This is called ’ Bioregenerative’ , a renewable symbiotic relationship between plants, humans, and microbes.The humans produce the carbon dioxide and nutrients via their waste that the plants need, in turn they produce the oxygen and food that the humans need.The microbes make the process possible.Also, there is the social and symbolic value.When Earth life is actually growing on another planet that is likely to reignite interest in space travel: public interest and support for space travel is essential if governments are to be permitted to invest the huge sums of money required for such experimentation.
        Questions 56—60 Complete the following schema with no more than three words for each blank according to the passage.


选项

答案encounter problems

解析 根据题意定位至文章第二段。 原文倒数第三句提到“Using bioengineering the mustard seed genes can be combined with jellyfish genes that make the plants glow with a soft green aura when they encounter problems.”由此可知,当遇到问题时,水母基因可以使芥莱种子发出柔和的绿色光环,即实验的第二步是观察植物是否遇到问题,故本空填encounter problems。
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