Q5 - Scientist: Earth's average annual

[dan]

5. (B)
Question Type: Weaken the Conclusion
The scientist concludes that the buildup of minor gases in the atmosphere is the primary cause of the earth’s warming. To weaken this argument, we want to look for a counter premise that either (1) casts doubt on the minor gas theory, or (2) presents a more compelling alternative cause for the warming. Answer (B) certainly casts doubt on the minor gas theory. If most of the warming occurred before the minor gas buildup, it doesn’t make much sense to say that minor gases were the cause.

(A) is out of scope. The source of the gases is irrelevant.
(C) is very tempting, as it provides what seems to be an alternative explanation: more solar radiation would mean higher temperatures. But, this does NOT say that the solar radiation was higher overall in the last century than in previous centuries, but simply that some years had higher solar radiation than others during the last century.
(D) is irrelevant. We care about what’s keeping heat in not what’s keeping heat out.
(E) can be an attractive answer, but be careful. Answer (E) actually strengthens the argument! This is the exact opposite of what we want.


#officialexplanation

[gplaya123]

Hey Dan, I have a quick question.
I fell into the trap, thinking that C does provide an alternative explanation...

1) Could it be that this answer is wrong because this answer choice requires an additional assumption, that solar radiation is hot? (I don't know... it's sort of intuitive to think that it is hot... but just to make sure...)

2) I thought that for a weakening question, anything that decreases the likelihood of the conclusion being a valid one could be the answer..
Would you say that this question is poorly written?