Final answer:
Acquisition of land was a primary motivating factor in early U.S. Indian policy, and the recruitment of native allies was critical to the Spanish conquest of the Aztecs. Indian alliances were also key in European power dynamics in the southeast.
Step-by-step explanation:
The statement that the acquisition of land was the most important motivating factor in the formulation of early U.S. Indian policy is true. Early U.S. policy towards Indigenous peoples was heavily influenced by the desire to expand territory for colonial settlements, economic exploitation, and political control. This often resulted in displacement and unfair treaties for Indigenous peoples. The statement that recruiting native allies played an important role in the Spanish conquest of the Aztecs is also true. The Spanish forces, led by Hernán Cortés, formed strategic alliances with disaffected native groups who were subjected to Aztec rule, which were crucial in undermining the Aztec empire.
Indian alliances were indeed a means of establishing power for European empires in the southeast, which is evident through various historical accounts detailing European interaction and relationships with different Indigenous tribes.