Which event led to world war 1?
a. a german spy was caught in france
b. the russian czar declared war in germany
c. a serbian nationalist assassinated the austrian archduke
d. france and germany went to war over colonial lands in africa

What was the purpose of the u. s navy's convoy system

How long was the peasants’ work day?

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 a. primary sources are historical documents, and secondary sources are modern-day documents.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