Answer:
Mainly the Soviet Union backed the Viet Minh otherwise known as the North Vietnamese as the USSR backed many communist/socialist countries around the world in small proxy wars against the United States to try and gain influence and expand communism. So your answer would be the Union of Soviet Socialist Republics.
The southern economy depended very much on slavery, using slaves to pick cotton and other things for the farmers. Normally the more slaves you had, the richer you were. Slaves were very important to the southern economy because southerners depended solely on slaves' labor. The families were affected when they could no longer keep slaves so the South was very mad because this was their main source of production. Once rich families no longer had laborers, causing loss of money and crops. The whole southern economy was affected by the loss of slaves but when slaves were allowed the southern economy was booming.
From what i can actually read it look to be correct.
