Structural analysis would be especially appropriate for determining the meaning of which word?

Structural analysis is a method used to understand the meaning of a word by breaking it down into its individual parts: prefixes, roots, and suffixes. In this context, "impassable" is particularly suitable for structural analysis because it consists of the prefix "im-" (meaning not) and the root "pass" (to go through) combined with the suffix "-able" (capable of). This dissection helps to determine that "impassable" means "not able to be passed through."

In contrast, the other words—"elephant," "interim," and "examine"—do not lend themselves as clearly to structural analysis. "Elephant" is a specific noun without apparent prefixes or suffixes that contribute to its meaning. "Interim" is a single word with Latin origins that does not exhibit a clear breakdown into meaningful components in English. Similarly, "examine" has a root but lacks a meaningful prefix or suffix that would help in analyzing it structurally. Thus, "impassable" stands out as the best choice for structural analysis due to its clear morphological components, which aid in understanding its meaning.