What happened during the columbian exchange?
a. spanish explorers traded food for gold in latin america.
b. columbus returned to the americas six times.
c. plants, animals, diseases, and people moved among continents.
d. thousands of people from the americas migrated to europe.

What is the main difference between primary and secondary sources? a. primary sources are historical documents, and secondary sources are modern-day documents. b. primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c. primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d. primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.