Answer: A
Explanation: People aren't slaves as a choice, when Africans sold their slaves or conquered enemies as slaves to other Africans, Europeans, and US citizens, the Americans that purchased them and brought them to the US was forceful.
A Mexican cavarly unit attacked a group of U.S. soldiers in a disputed zone who were under the command of General Zachary Taylor. This is what sparked the Mexcian-American War and the United States had a "manifest destiny" to spread across the continent to the Pacific Ocean. The U.S. won the war, gaining control over California, Utah, Nevada, Arizona and New Mexico.
