Study Guide for Chapter 22 From Neutrality to War Key Content Terms Define and explain the significance of each Key Content Term listed below. Central powers Allied powers U-boat Lusitania unrestricted submarine warfare Sussex pledge preparedness movement Zimmerman note Key Content Questions Consult History Alive! Pursuing American Ideals and your reading notes to answer the following questions. Explain how conditions in Europe caused an assassination to turn into a global conflict. Describe the advantages and disadvantages of American neutrality at the outset of World War I. How did the use of unrestricted submarine warfare contribute to anti- German sentiment in the United States?