The expansion of the continental United States was made complete by A. the Louisiana Purchase
B. the annexation of Texas.
C. the Mexican Cession.
D. the Gadsden Purchase.
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I think the Louisiana Purchase

hope this helped

Treaty of Guadalupe Hidalgo

Explanation:

The Treaty of Guadalupe Hidalgo, signed by chief negotiator Nicholas P. Trist on February 2, 1848, and approved by the U.S. Senate on March 10, 1848, ended the war, opened a dramatically different chapter in U.S. relations with Mexico, and nearly completed America's continental empire.

a, he promoted disarmament

(202 bc - 220 ad) dynasty started by lui bang; a great and long-lasting rule, it discarded the harsh policies of the qin dynasty and adopted confucian principles; han rulers chose officials who passed the civil service exams rather than birth; it was a time of prosperity