He battle of antietam severely weakened the union army. shifted control of the civil war from the south to the north. was the last battle that took place in the eastern united states. convinced europe to support the confederacy.

The Battle of Antietam is also known as the Battle of Sharpsburg and was fought on September 17, 1862 in the American Civil War. It was the war of the Confederacy against the Union and was fought in the Southern United States.  

Question:  The Battle of Antietam

A. severely weakened the Union army.

i think you may have asked this twice, but i answered one of the