Like many music genres, the term of Rhythm and Blues is an umbrella term that covers a variety of music, referring to the rhythm of the backbeat that was influenced by rock and roll, while the chord changes were reminiscent of the blues. R&B’s origins can be rooted in jazz, blues, and gospel.
The term gospel is a reference to the 'good news' of salvation, but outside Christian circles, it is a reference to a musical style that takes its roots from African-American Christian celebrations. The style, with its fast beats and call-and-response was used for those who would share and testify at churches in the American South.
To a large extent Jazz evolved from the Blues, but is generally a lot more upbeat and laid-back. Jazz has a dedicated following of music lovers who appreciate the skill and talent displayed in the extensive improvisation by musicians, with virtually no two performances being exactly the same.