Organum added what to gregorian chants?

guitar music
a choir
a second voice
lyre accompaniment

Ineed some on finding music. i have a nephew who is into rap, but when i find a rap song, it seems to either be too old for his taste or to him it isn't good enough. can someone suggest some good music for me to see if he likes it or not?

What should i say so i can switch my instrument

Which artist is often considered the leader of the hudson river school and poignantly set up contrast between the cultivated east and the wild west in the united states?