In 1845 united states annexed the republic of

Republic of Texas

Explanation:

The Republic of Texas was recently created following the victory over Santa Anna & their successful independence from Mexico. This soon followed with Texas asking to join the US as a "slave state" (you must remember this is before the American Civil War), & was allowed to join the "Union" (later becoming the Confederacy) soon after.

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false, the two are unrelated

answer; i believe the two groups were irish immigrants and chinese immigrants;