The Age of Imperialism During the late nineteenth and early twentieth centuries, the United States pursued an aggressive
policy of expansionism, spreading its political and economic influence around the globe. Growth in
international trade occurred from the late 1800s to World War I: the first era of true "global
economy

Re-state in your own words:

After temporarily resolving the problems of Reconstruction and Industrialization, Americans began to resume the course of expansion. The horrors of the Civil War had interrupted the original Manifest Destiny that began in the 1840s. Now, as pioneers settled the last western frontiers, expansionists looked yet farther to the west—toward Asia and the Pacific.

Explanation:

b europeans take corn to africa. corn becomes an important crop there.