Sudden changes in society are often described as revolutions. Advances in technology can result in revolutions in science and the workforce. Dissatisfaction with a government can lead to a political revolution. Under what circumstances is it likely that these changes will occur? Are there circumstances in which these changes should not occur?

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 a. primary sources are historical documents, and secondary sources are modern-day documents.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