Rivers and what made it easy to ship crops out of the south and bring in other products

During the end of the 19th century and the early 20th century the was becoming one of the most popular instruments in america? banjo fiddle guitar pianola (player piano) tambourine

What was america's response to the holocaust before the war? what could the us have done differently?

What did kublai khan learn from the chinese advisers he consulted?