Central and eastern europe experienced ethnic tensions in the early 1900s primarily because

Ethnic tensions in Central and Eastern Europe reveal many things, some are about social class, religious belief, boundary or territorial crosscutting possession of Ethnic group, the rise of industrialization in their respective territory or boundary, political consciousness, nationalism, the birth of state or nation and monarchy issue.

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Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.