Final answer:
New Orleans served as the link between American agriculture and European buyers.
Step-by-step explanation:
The port that became a link between American agriculture and European buyers was New Orleans. New Orleans rose in prominence and importance during the cotton boom in the first half of the nineteenth century. Steamboats transported cotton from plantations along the Mississippi River and throughout the South to the port at New Orleans, which served as a major hub for exporting cotton to European buyers.