Following Lincoln’s assassination, the emancipation of enslaved people became official when

states ratified the 13th Amendment

Explanation:

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A. states ratified the Thirteenth Amendment.

Explanation:

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers