Study the graphic image. What concepts can be illustrated by this image?

Nationalism Yes No
mercantilism Yes No
militarism Yes No
imperialism Yes No
slave trade Yes No
Westward Expansion Yes No

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 a. primary sources are historical documents, and secondary sources are modern-day documents.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.