What did eli whitney invent that changed slavery in the us?

When lincoln was first elected president, he hoped to prevent war by allowing (1) in the united states. as time went on, he saw the (2) of the war as putting an end to slavery. once the civil war was over, president lincoln did not intend to (3) the south. he felt everyone had suffered enough. he wanted to the south, and the whole country, rebuild. the process of rebuilding the country following the civil war was called (4) the official surrender by general lee to general grant occurred at (5) and the terms were generous to the south. the terms of surrender said that the southern soldiers could go (6) and would not be prosecuted for (7) it also said that they must surrender their (8) but could keep their (9) officers were allowed to keep their (10) in order to make the achievements of the war permanent, three (11) were added to the u.s. constitution.