Advantages
Slavery made a large contribution to the growth and development in the US
Slaves helped clear a lot of woods and forests and built important railroads and roads that are still used today
Slaves picked cotton, which helped the US in the future and has become the US’s most valuable export
Farmers didn’t pay slaves so it helped them financially
Many of the slaves would have lived in poverty and probably starved to death if not for slavery. Although it was cruel, by being slaves they were fed and kept alive, which is better than starving to death.
Slavery boosted the US’s economy hugely, as they were selling and trading things, and not having to pay for the labour.
The work that the African slaves did had to be done, so if they didn’t do it, America would probably take slaves from another country instead.
Africa was already involved in slavery
The enslaved people were not fit for work as they were uneducated
The bible stated that slavery was accepted and okay
Unless the slaves rebelled, they were not ill-treated
If Britain didn’t enslave people other countries would get involved

Disadvantages
The hours they worked were too long which caused the slaves to be exhausted
If they could no longer work they were beaten or sold to new masters
Slaves weren't given the legal right to marry, own property, testify in court, or earn their freedom
They were punished by being beaten, given short rations and being threatened that the master would sell their family, and the slave