Which statement provide the best explanation of the term columbian exchange? a) people on continents with very different climates, cultures and lifestyles suddenly meet and exchange crops, ideas, and diseases. b) families with long lost relatives are reunited after being separated for a generation or more. c) civilizations that had been at peace before suddenly start figthing over the ownership of land they used to share. d) people who are descended from christopher columbus work together to understand and control worldwide diseases.