Respuesta :
Answer:
The Louisiana Purchase
Explanation:
The purchase doubled the size of the United States, greatly strengthened the country materially and strategically, provided a powerful impetus to westward expansion, and confirmed the doctrine of implied powers of the federal Constitution.
The answer is the Louisiana purchase. It doubled the size of the US, greatly strengthened the country materially and strategically, provided a powerful impetus to westward expansion, and confirmed the doctrine of implied powers of the federal constitution.