What were the negative effects of American slavery

What were the negative effects of American slavery. What were the negative effects of American slavery (Transatlantic human traffic) on the economic, cultural and social development of African societies?  Do you think these effects paved the way for the European colonization of Africa and further exploitation of African persons by European societies?  Remember, European settler colonizers occupied large areas of Africa all the way to the 20th century; furthermore, foreign companies are still in control of African labor and resources in several countries.  Reflect on the numbers provided by our textbook, the community structures, family units, roles of absent persons and any other item that can produce a complex picture of the results of slavery.

What were the negative effects of American slavery