Answer:
Napoleon's decision to sell Louisiana to the United States was key to ensuring America's further development as a world power. The decision of the French leader was due to the fear that he had that Great Britain would take control of the territory, with which the sale to the Americans put a limit to British colonialism in the region.
Now, the Louisiana acquisition allowed the United States to consolidate its westward expansion, while for the first time able to dominate most of the North American continent. In this way, with this territorial dominance and a greater presence on the continent, expansionism based on Manifest Destiny was exacerbated and the United States began to acquire new territories, increasing its economic productivity and its dominance over other countries.
I think you should use a comma instead of a colon. I am unsure of the question but I hope this helps.
