One way to determine which planets outside the solar system might harbor life is to look for telltale signs in their light. Livi

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问题     One way to determine which planets outside the solar system might harbor life is to look for telltale signs in their light. Living organisms create a chemical disequilibrium in their environment, typically indicated by a molecule whose presence can be explained only if some presence is continually regenerating it. For example, Earth’s atmosphere contains oxygen because photosynthesis produces it faster than it is lost through processes such as the rusting of iron in rocks. However, chemical disequilibrium does not necessarily indicate the presence of life because, as in the case of methane on Mars, the imbalance could arise through nonbiological processes.
According to the passage, which of the following about the presence of a chemical disequilibrium is true?

选项 A、It may indicate the presence of life.
B、It may be the product of a nonbiological process.
C、It is something that typically is short-lived.

答案A,B

解析 A项对应文章前三句。B项对应第四句。C项文中未提及。
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