World war 1 broke out in 1914 because a group of Serbian nationalists (The Black Hand) assassinated the duke of Austria-Hungary. Austria -Hungary threatened Serbia with a bunch of wishes that they wanted Serbia to due for them. Due to the treaty between Serbia and Russia, Serbia said no. Germany, who had a treaty with Austria-Hungary threatened to attack if Russia mobilized its army. Russia did and Germany invaded Belgium. This brought Great Britain and France into the war.
Invasive species of flora and fauna and communicable diseases were a byproduct of the Colombian Exchange
In the State government Is where they hold power.
Checks and balances is a system were the goverment checks the other two braches of goverment, and balance them out. so if the execuative branch gets to much power, the judicial and legislative branches bump down the power of it.