#18 - Concept Reference, Must Be True

[Administrator]

Complete Question Explanation

The correct answer choice is (E).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[jlam061695]

Can someone explain to me why E is correct? The fact that it's a technique used to detect elements in the sun that are "less than 10 percent of its mass" is unsupported; there is no mention of "mass" anywhere in the passage. The passage seems to be vague in that it doesn't mention a unit. Was I supposed to infer that a body "composed largely of iron" to mean that "composed largely of iron mass-wise"? Or could the passage also be referring to weight, volume, density, etc.?

[Adam Tyson]

A better question to ask, jlam, might be "why is E better than the other four answers?" You've gotten a little hung up on the science here, I think, but keep in mind that our test is not written by scientists, and they may not have thought of the differences between, say, mass and volume.

The passage tells us that Payne used the spectroscopic data to determine that "90 percent of the sun is hydrogen" and that the rest included helium and some iron, among other elements. Could that be interpreted as 90% of the volume or weight? Perhaps. Could it be interpreted as 90% of the mass? Also perhaps (and, thinking like a layman rather than a scientist, that seems the most likely meaning of "90 percent of the sun").

If she could use spectroscopy to determine that 90% is hydrogen and that iron is only a portion of the remaining 10%, that sounds an awful lot like answer E. Perhaps, if we wanted to mirror the passage a little more precisely, E could have said "content" instead of "mass". Still, we don't want to let that spoil our day, for two reasons. First, that requires you bringing in some outside information of your own, which is generally a no-no on this test. Second, we aren't looking for perfect answers on this test, or even good ones. We are looking for the best answer of those provided. E is best because it could be correct (and it seems to be a pretty reasonable interpretation that it is), while none of the others have any support at all no matter how you interpret them. Since E could be right, if you interpret "90 percent of the sun" to mean 90% of its mass, it's the one that is most strongly supported and must be the credited response.

Avoid that outside information, and don't be too picky with these answer choices. You don't have to love an answer, you just have to hate it less than you hate the others. Love the one you're with, as the song says!