单选题Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occurred in Antarctica at the time the fossilized trees lived. Which of the following is an assumption on which the argument depends?AThere are fossilized nondeciduous trees from Antarctica that bear frost rings.BDeciduous trees are more likely to bear frost rings than are other tree varieties.CThe process of fossilization does not completely obscure frost rings in deciduous trees.DPresent-day deciduous trees are more sensitive to changes in temperature than were the deciduous trees of ancient Antarctica.EProlonged and unseasonable frosts that might have occurred in Antarctica when the now-fossilized trees were still living did not always produce frost rings in deciduous trees.
单选题
Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occurred in Antarctica at the time the fossilized trees lived. Which of the following is an assumption on which the argument depends?
A
There are fossilized nondeciduous trees from Antarctica that bear frost rings.
B
Deciduous trees are more likely to bear frost rings than are other tree varieties.
C
The process of fossilization does not completely obscure frost rings in deciduous trees.
D
Present-day deciduous trees are more sensitive to changes in temperature than were the deciduous trees of ancient Antarctica.
E
Prolonged and unseasonable frosts that might have occurred in Antarctica when the now-fossilized trees were still living did not always produce frost rings in deciduous trees.
参考解析
解析：
文段由“霜冻年轮没有出现在落叶树的化石中”这一现象，得到结论“南极洲的落叶树上没有霜冻”，但是如果形成化石的过程中会是霜冻年轮消失，那么该结论就不成立，故文段的推论蕴藏着C项假设，所以本题选C项。
文段由“霜冻年轮没有出现在落叶树的化石中”这一现象，得到结论“南极洲的落叶树上没有霜冻”，但是如果形成化石的过程中会是霜冻年轮消失，那么该结论就不成立，故文段的推论蕴藏着C项假设，所以本题选C项。
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