useless trivia: What Word Means: The Ancestors Of The Ainu People?

Questions

The "G-string" in Bach's well-known Air refers to a string on what instrument ?

Tchaikowsky's "Marche Slave" is based on a folk-song of what national origin ?

Which pianist-composer permanently injured his hand by wearing a home-made contraption designed to immobilize the fourth finger while practising ?

French writer George Sand is remembered for her affair with which composer ?

Bach's "Goldberg Variations" are best known today through the recording of this Canadian pianist. ?