What action provided the basis for the Emancipation Proclamation?

From the first days of the Civil War, slaves had acted to secure their own liberty. The Emancipation Proclamation confirmed their insistence that the war for the Union must become a war for freedom. It added moral force to the Union cause and strengthened the Union both militarily and politically.

Explanation:

yes, there are senators in each state

answer; (c) slaves brought to the americans from africa;