<p>You should be able to determine that the impact craters are not ostensibly visible due to “erosion [that] may have smoothed its surface.” Hence, you can eliminate magnitude. The verb smooth is used, so you can eliminate ruggedness (why would the surface be rugged if erosion has smoothed it?). I hear the word panoply, and I think of the word monopoly, which implies ubiquity. Certainly the craters are not ubiquitous.</p>
<p>We are now left with spate and paucity. If you plug in spate for the sentence, it sounds odd. The -ity ending of paucity works better for the sentences, as it suggests a quality. Therefore, I would go with paucity.</p>
<p>Now, it would be slightly more difficult to do that process not knowing the meaning of the word paucity. However, I have to ask the question: how difficult of a word is ‘paucity?’ I simply would use the POE outlined above to reinforce my knowledge of the word paucity in this case.</p>
<p>As for the person who asked the question about how to make the connection between “Tenacious D” and tenacity, I think rock bands are all about this sense of rebellion and having “the balls to do something.” For a semi-comical band inclusive of Jack Black, an adjective along the lines of tenacity is fitting. And in the case of tenacity, I actually used this logic on a standardized test once (the memory of thinking of Jack Black to understand the meaning of tenacity has since permanently engraved into my mind the meaning of the word).</p>