Which award's scope does not lend itself to a particular function or activity?

The Individual Legacy Award is indeed the choice that stands out in this context. This award is designed to recognize individual achievements and contributions that are significant and impactful over time, rather than being tied to a specific activity or function within the USAF.

Unlike other awards, which may focus on particular functions — such as the Outstanding Unit Award that honors units for their effectiveness in achieving mission goals, or the Best Installation Award that recognizes overall excellence in installation management — the Individual Legacy Award acknowledges broader, long-lasting influences and contributions made by individuals.

It honors personal legacies that demonstrate an individual's commitment to service that may not fit neatly into a single event or activity. Thus, the scope of the Individual Legacy Award is more expansive and does not lend itself to a particular function or activity as some of the other awards do.