Passage Summary: As you go higher up, the air gets thinner. Because Mexico City is higher up than Panama City, it must have thinner air.

Conclusion: Mexico City has thinner air than Panama City.

Reasoning: There is a direct correlation between altitude and air density, and Mexico City has a higher altitude than Panama City.

Analysis: The structure of this argument is a straightforward application of a general principle to a specific comparison. It follows the pattern: 'The more of X, the more of Y; A has more X than B; therefore, A has more Y than B.' To find the parallel, look for an answer that establishes a proportional relationship between two variables and then uses that relationship to rank two specific items. Avoid choices that use absolute terms like 'all' or 'none' if they don't involve a comparative ranking.