APES- Clear up a couple of questions for me?

ColdEggNog · 05-12-2008, 05:34 PM

My class was given a set of multiple choice questions along with the answer key, and I understand most of them, but some of them I fail to understand. Can somebody explain them to me?

1) Many sceintists maintain that a rise in sea level has occurred in the last hundred years as a result of global warming. If this is true, which of the following factors best explains such a rise?
A. Increased precipitation
B. Increased cloud cover
C. Increased evapotranspiration
D. Thermal expansion of the ocean
E. Melting of permafrost

2) If the population of a country grows at a rate of approximately 5% per year, the number of years required for that population to double is closest to:
A. 5 years
B. 10 years
C. 15 years
D. 25 years
E. 35 years

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The answers are 1) D and 2) E.

Why would the 1st one not be E? I always thought that a big concern for global warming was the melting of ice caps which would in turn raise sea level? Why is is thermal expansion instead?

And for the 2nd, doubling time is 70/(growth rate %), so it would be 70/5 = 14%, which should be choice C. Did I do something wrong? Apparently, the answer's E.

Thanks in advance.

AMX · 05-12-2008, 05:46 PM

1. When water is heated it expands, so when the oceans are heated by global warming, they expand. Permafrost =/= ice caps.
2. I get C as well.

PrescitedEntity · 05-12-2008, 05:52 PM

1) Thermal expansion is worse than permafrost melting because there's a LOT of ocean - and thus, a lot of water - that can expand. While permafrost isn't equivalent to ice cap, its melting can be expected to raise ocean levels, but not that much. It's like the ice in the tundra melting.

2) I'm getting 14 years. Not helpful.

ColdEggNog · 05-12-2008, 05:53 PM

Alright I think I kind of get the first one now, thanks

I'm thinking maybe the answer key was wrong for the second, because I don't see where 35 comes from.

Thanks guys.

Zachsta · 05-12-2008, 08:42 PM

Those questions are from a past CollegeBoard test...your teacher must have simply written the question out wrong, the real question asks for the doubling time for a pop. with a 2% growth rate...thus the 35.