Prolonged and unseasonable frosts produce frost rings in deciduous tre

Question

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.

Mansoor50 · Answer

CAn an expert tell me why B is not correct?

my line of thought: the arg is tight which means there is NO other way of detecting P/U frosts other than frost rings in D trees.

therefore, the assumption has to eliminate all other sources of P/U frost detection. 
which brought me to choose B

Kinshook · Answer

Premise 1: Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. 
Premise 2: Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. 
Conclusion: Hence, it is unlikely that such frosts occurred in Antarctica at the time the fossilized trees lived.

Negation test
C．The process of fossilization does not completely obscure frost rings in deciduous trees.
If we negate C, the conclusion falls apart

IMO C

yashwardhan · Answer

Can someone explain why E cannot be the correct answer? Negating E breaks the conclusion as well!

NeverEverGiveUp11 · Answer

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.

The negation of E is
Prolonged and unseasonable frosts that might have occurred in Antarctica when the now-fossilized trees were still living always produced frost rings in deciduous trees.

This negated version supports the premise that "Prolonged and unseasonable frosts produce frost rings in deciduous trees". By negating we need to break either the reasoning used in the argument (that is the link between the premise and conclusion) or the conclusion of the argument. Thus, the negation of E doesn't help to break the conclusion or the reasoning used.

Here the reasoning used by the argument is that evidence of no rings in the fossils suggests that it is unlikely that such frost occurred in Antarctica. So we need to weaken this reasoning.

On negating B we get that " process of fossilization completely obscures the rings" ...if this is the case then we can not certainly say that the frost occurred in Antarctica. hence breaks the conclusion

BALAGURU · Answer

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

Prolonged and unseasonable frosts  produce > frost rings - deciduous tree ( say in hot climate)
 No frost rings - FOZZILIZED deciduous trees ( in cold area, say)
.'. Such frost - Prolonged and unseasonable --> din happen

The only extra thing that was considered was FOZZILIZED , hence there is the key....

Hence , C

jonfuckingsnow · Answer

E acts as a weakener, as it gives reason that frost rings may not have formed even if frosts occurred in Antarctica

Dooperman · Answer

Assumption

A. There are fossilized nondeciduous trees from Antarctica that bear frost rings.
Doesn't matter. Argument is about fossilized trees.

B．Deciduous trees are more likely to bear frost rings than are other tree varieties.
Doesn't matter. Argument is not about comparison of Deciduous trees with other varieties.

C．The process of fossilization does not completely obscure frost rings in deciduous trees.
Yep. This destroys the doubt that rings were present once however obscured due to other reasons.

D．Present-day deciduous trees are more sensitive to changes in temperature than were the deciduous trees of ancient Antarctica.
Doesn't matter. Argument is about fossilized trees.

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.
Passage says "Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates". This options challenges the facts of passage. Hence incorrect.

VerbalBot · Answer

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Prolonged and unseasonable frosts produce frost rings in deciduous tre

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Prolonged and unseasonable frosts produce frost rings in deciduous tre

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