Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.
Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?
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AThere are millions of planets orbiting stars around which astronomers have not attempted to detect planets.
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BThe best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.
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CA planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.
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DThe smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.
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EThe observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.
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正确答案: D