Question

What werw the causes for the first world war to take place?

Answer 1

On 28 June 1914, Gavrilo Princip who was a Bosnian Serb student shot and killed Archduke Franz Ferdinand the heir to the Austro-Hungarian throne with his wife Sophie Chotek in Sarajevo and the capital of Bosnia which had been annexed by Austria-Hungary in 1908. Princip was a member of Young Bosnia, a group whose aims included the unification of the South Slavs (Black Hands) and independence from Austria-Hungary. The assassination in Sarajevo set into motion a series of fast-moving events that escalated into a full-scale war. Austria-Hungary demanded certain actions by Serbia to punish those responsible for the assassination. Austria-Hungary declared war on Serbia when it was deemed that Serbia had failed to fully comply. Many major European powers came to be at war with each other within a few weeks. This was due to overlapping of agreements for collective defense and the complex nature of international alliances at that time. However, the conflict also had deeper causes which were multiple and complex. In short, the immediate cause of the first World War was Sarajevo Crisis. 

Plz mark it brainiest answer because I have to search my history copy and then i wrote this answer for 20 minutes.