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  3. Life in the Universe Many scientists today are convinced that life exists elsewhere in the universe-life probably much like

Life in the Universe Many scientists today are convinced that life exists elsewhere in the universe-life probably much like

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问题                         Life in the Universe
    Many scientists today are convinced that life exists elsewhere in the universe-life probably much like that on our own planet. They reason in the following way.
    As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
    Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.
    Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.
    Finally, life could evolve only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.
    If we suppose that every star in the universe has a family of planets, then how many planets might support life? First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.
    This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.
Astronomers believe that matter in different parts of the universe______.
选项 A、has different laws
B、has one common law
C、shares the same laws
D、shares no common law
答案C
解析 推断题。根据第二段前两句：As far as astronomers can determine, the entire universe is built of the same matter．They have no reason to doubt that matter obeys the same laws in every part of the universe．天文学家现在可以确定整个宇宙是由同种物质组成的。他们没有理由怀疑宇宙的每一部分中的物质都遵守同样的法则。可以推断C为正确选项。
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