Which of the following functions is specific to the US Army?

The function specific to the US Army is the occupation of land areas. This responsibility falls squarely within the purview of ground forces, which are primarily tasked with securing and holding territory, an essential component of land warfare strategy. The Army focuses on land operations, engaging in both offensive and defensive operations while working to maintain control over geographical areas. This includes not only the initial capture of land but also the subsequent stabilization and governance of those regions.

In contrast, operations at sea pertain to naval forces, while Navy reconnaissance specifically relates to the duties of the Navy in gathering intelligence from maritime environments. Aerial combat operations typically involve the Air Force, which conducts missions related to air superiority, close air support, and strategic bombings. Thus, while there may be some overlap in joint operations among the branches, the occupation of land areas is fundamentally a role assigned specifically to the US Army, aligning with its primary mission of land warfare.