Explain: How is the 1917 German policy of "unrestricted submarine warfare policy" different than what they were doing with their U-boats back in 1915?

Ahistorian who compares the expansion of political systems to the expansion of economic systems is organizing history by

Which of these did the soviet union do in 1961? it built a wall through berlin to keep people from moving to the west. it used force to destroy a wall the united states had built in berlin. it convinced the british and french to merge their zones in berlin with the soviet zone. it threatened to bomb berlin if the united states did not leave within 30 days.

Which of the following could be seen as a weakness of a two-party system? a. the two-party system limits voters' options in electing officials. b. the two-party system limits debate on issues. c. the two-party system limits the range of solutions that will be considered. d. all of these are weaknesses