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  3. Studies of meteorites and comets suggest that organic molecules are widespread a

Studies of meteorites and comets suggest that organic molecules are widespread a

游客2024-01-02  55
问题 Studies of meteorites and comets suggest that organic molecules are widespread among both asteroids and comets. Because each body in the solar system was repeatedly struck by asteroids and comets during the period known as the heavy bombardment (about 4 billion years ago), each body should have received at least some organic molecules. However, these molecules tend to be destroyed by solar radiation on surfaces unprotected by atmospheres. Moreover, while these molecules might stay intact beneath the surface (as they evidently do on asteroids and comets), they probably cannot react with each other unless some kind of liquid or gas is available to move them about. Thus, if we limit our search to worlds on which organic molecules are likely to be involved in chemical reactions, we can probably rule out any world that lacks both an atmosphere and a surface or subsurface liquid medium, such as water.
The word "intact" in the passage is closest in meaning to ________.
选项 A、buried
B、whole
C、confined
D、active
答案 B
解析 intact的本意为“完好无损的”，B项意为“完整的”，为其近义词。如果不知道intact的含义，还可以通过上下文推断出来。这个单词位于该段的第4句，说的是这些有机分子在大气层下的状况。其前一句为关键解题句，该句提到，在没有大气层保护的情况下，这些有机分子会被太阳辐射摧毁。因此，可推测stay intact在此处应该是与be destroyed相反的一个状况，B项最符合该处语境。
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