Which of the following is a primary function of the Army?

The primary function of the Army is to conduct land combat operations to defeat enemy forces. This role is foundational to the Army's purpose and is essential for maintaining national security and achieving military objectives. The Army is specifically organized and equipped for ground warfare, which includes seizing and holding territory, maneuvering forces, and engaging in direct combat with enemy troops.

While the Army may play supporting roles in other areas, such as assisting in amphibious operations or contributing to joint operations that include air components, its core mission focuses on land-based operations. Engaging in diplomatic negotiations, while important for military strategy and relationships, is not a direct function of the Army. Therefore, conducting land combat operations is central to the Army's identity and operational effectiveness.