What group of people was taken and sold as slaves?

Why this is the answer

The people taken and sold as slaves were Africans. European countries with colonies in the Americas took people from Africa by force, shipped them across the Atlantic and sold them; the first enslaved Africans were brought to Jamestown in 1619, and millions more were forced to work on farms. Slavery became the deepest contradiction of a country founded on the idea that all people are created equal, and it was a cause of the Civil War. Either official answer is accepted: Africans, or people from Africa.