Final answer:
Europe had the most significant impact on the formation and development of the United States, primarily through colonization, cultural influence, and the establishment of colonial societies that laid the groundwork for the nation.
Step-by-step explanation:
The continent that had the biggest impact on the formation and development of the United States is Europe. From the arrival of European colonists, who established the first colonies that would later become the United States, to the influx of European goods, ideas, and diseases that shaped the continent, Europe's influence was fundamental.
Colonial societies became segmented and divided along religious and racial lines. While all three continents played roles in the United States' formation—America with its geography providing isolation and resources, Africa through the transatlantic slave trade deeply affecting the societal structure, and Europe primarily through colonization and cultural influence—it was European colonization and governance that laid the groundwork for the future nation.