For centuries, explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic an

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问题     For centuries, explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic and nationalistic. Columbus went west to look for better trade routes to the Orient and to promote the greater glory of Spain. Lewis and Clark journeyed into the American wilderness to find out what the U. S. has acquired when it purchased Louisiana, and Apollo astronauts rocketed to the moon in a dramatic show thanks for technological muscle during the cold war.
    Although their missions blended commercial and political-military imperatives, the explorers involved all accomplished some significant science simply by going where no scientists had gone before.
    Today Mars looms as humanity’s next terra incognita(未探明之地). And with doubtful prospects for a short-term financial return, with the cold war a rapidly fading memory and amid a growing emphasis on international cooperation in large space ventures, it is clear that imperatives other than profits or nationalism will have to compel human beings to leave their tracks on the planet’s reddish surface. Could it be that science, which has long played a minor role in exploration, is at last destined to take a leading role? The question naturally invites a couple of others: Are there experiments that only humans could do on Mars? Could those experiments provide insights profound enough to justify the expense of sending people across interplanetary space?
    With Mars the scientific stakes are arguably higher than they have ever been. The issue of whether life ever existed on the planet, and whether it persists to this day, has been highlighted by mounting evidence that the Red Planet once had abundant, stable liquid water and by the continuing controversy over suggestions that bacterial fossils rode to Earth on a meteorite(陨石)from Mars. A more conclusive answer about life on Mars, past or present, would give researchers invaluable data about the range of conditions under which a planet can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth, the finding would provide the first concrete clues in one of the deepest mysteries in all of science: the prevalence of life in the universe.
The passage tells us that proof of life on Mars would _____.

选项 A、make clear the complex chemistry in the development of life
B、confirm the suggestion that bacterial fossils travelled to Earth on a meteorite
C、reveal the kind of -conditions under which life originates
D、provide an explanation why life is common in the universe

答案D

解析 细节题。通过阅读文章最后一句If it could be established that life arose independently on Mars andEarth,the finding would provide the first concrete clues in one of the deeoest mysteries in all ofscience:the prevalence of life in the universe.可知这与题干中的“有关火星上有生命的证据”有关。此句译为:如果能够证明生命独立地存在于火星和地球上,这一结果会对科学中最深奥的奥秘“生命普遍存在于宇宙中”提供第一手的具体的信息资料。选项D是说为“宇宙中生命是普遍存在的”提供证据,只有D符合原文,因此是答案。
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