How did African Americans influence jazz?

Answer 1

African slaves were stripped, in a large degree, of their home cultures. As a group, they started making a new culture of their own. They made songs for work, for codes to meet, and for entertainment. As slaves were not formally educated in the arts, there was no training in music technique. They would often bend or slur the notes being played, and there was a fair amount of falsetto in the singing. These things all lent themselves to the later traditions of Jazz Music.

Answer 2

Generally speaking, yes. Although it is unsure as to exactly "who" invented jazz, all early progressions of jazz are easily traced back to African American communities. Nearly all later innovations on jazz styles, such as bebop and cool jazz, can be traced back to African American jazz legends. (Coleman Hawkins started bebop, and Miles Davis started cool jazz)

Answer 3

Yes, several white and creole people played jazz, like in New Orleans.