The Eastern Front or Eastern Theater of World War I (German: Ostfront, Russian: Восточный фронт, Vostochny front) was a theater of operations that encompassed at its greatest extent the entire frontier between the Russian Empire and Romania on one side and the Austro-Hungarian Empire, Bulgaria, the Ottoman Empire and the German Empire on the other. It stretched from the Baltic Sea in the north to the Black Sea in the south, involved most of Eastern Europe and stretched deep into Central Europe as well. The term contrasts with "Western Front", which was being fought in Belgium and France.
The system of checks and balances makes sure that one branch of gov. Doesn't get more powerful than the other by giving different powers to different branches. Like a certain branch can't do something without the "thumbs up" from the other branch. For example, the Executive Branch can veto bills from the Legislative Branch, but the Legislative Branch can override the veto. Hopefully that helped!!
During this era southerners were against letting slaves be free and many problems and disagreements came with this.