Thanks for the question! This one requires us to make a small deduction, it’s not quite stated explicitly/obviously in the passage. So we’re trying to find evidence that the two proposals discussed in the passage aren’t the only proposals that scientists have suggested can explain polarity reversal. Well, the discussion of the two proposals happens in the third paragraph. One of them is the heat-transfer hypothesis, and the other one is the asteroid-impact hypothesis. So where in the passage is evidence for other theories?
This occurs at the very end of the passage, at the end of the last paragraph. We’re told starting in line 59 that “theories that depend on extraterrestrial intervention seem less convincing than theories like the first,” where “the first” here refers to the heat-transfer hypothesis. But now we know that there are “theories like the first.” In other words, there’s at least two (since “theory” is pluralized here) other theories out there that are like the first. And that means that there are other proposals put forward to explain polarity reversal, and that’s what supports (D).
Hope this helps! Feel free to ask any other questions that you might have.
FelixOctober 15, 2020
Would you also be able to use line 30 "Several explanations for this phenomenon have been proposed"? Wouldn't 'several' imply more than two or is that too far of a stretch?
Nathnael-AlazarFebruary 1, 2021
^I was thinking the same thing. By definition (even for the LSAT definitions that I have looked up), "several" means 3 or more, so I'm assuming this is a fair explanation as well?
