Why did the assassination of Archduke Francis Ferdinand in Bosnia cause Germany to get involved?

Germany got involved in the First World War.

Explanation:

Archduke Franz Ferdinand was assasinated in Sarajevo, Bosnia, in mid-1914. He was the heir of the Austria-Hungary's throne. Austria-Hungary declared war on Serbia - it was a Russian ally - and because of its military alliance, Germany also had to declare war on Serbia and that put both powers in collision with Russia. In turn, Russia had an alliance with France. This system of alliances - and secret agreements - was a factor of the outbreak of WWI.