#15 - Global warming has contributed to a rise in global sea

[Administrator]

Please post below with any questions!

[jlam061695]

I did pick E for this one, but can someone provide a thorough explanation on why it's correct? I got E through the process of elimination, since I thought all of the other choices did not have to be true (well they had to not have been true, obviously)

[Kristina Moen]

Hi jl,

I'm glad you're asking about a question that you got correct. Many students gloss over questions that they got correct when they could learn a great deal from them (and identify their strengths!).

Since this a Must Be True, the four incorrect answers are all things that we can't infer - meaning, they could be true, could be false, or might even have to be false. The correct answer is something that absolutely, unequivocally must be true based on the stimulus.

So the premise tells us that there are multiple reasons why global warming has contributed to a rise in sea level - ice melts (turning into water) and when water is heated, the volume increases. We're also told that the rise has been lessened by artificial reservoirs.

So if you were to diagram this, you could write (where increased sea level is to the right, normally I'd write a vertical arrow but that's harder to do on the computer!):
Ice melts ->
Water heats ->
Reservoirs <-

Answer choice (E) is something that must be true. We can't determine how much water melted off the ice based on the sea level rise alone, since there are other things that affect the rise in sea level!

Is there another answer choice you would like to discuss?

[jlam061695]

Oh that makes sense now! E was the only answer choice I was hesitant about!

[relona]

Can someone please explain why is B incorrect?

[Adam Tyson]

Sure thing, relona! We cannot infer answer B (it is not something that "can most reasonably be concluded") because we have no information at all about what was happening before the reservoirs were built. Maybe rises in sea level were easy to explain back then, whether they were due to melting of glaciers, or warming of water, or something else? The stimulus says absolutely nothing about how easy or difficult it was to explain before or about how easy it is now. That's just a whole new idea that is not addressed by the facts given in the stimulus, and a requirement of new information is fatal to a Must Be True/Most Strongly Supported answer choice.