How did the versailles treaty cause ww2 dbq answer key?

There were two key components of the Treaty of Versailles that made a second world war more likely (rather than less likely) to happen. 

One issue was the heavy load of financial reparations that Germany was required to pay 132 billion marks for the civilian damage they had caused to the Allies.  That would be about 400 billion dollars in today's economic terms.  The amount was huge and oppressive and caused deep suffering in the German economy -- which allowed radical groups like the Nazis to rise to power by promising a return to German greatness.

The second issue was the "war guilt" clause of the treaty.  Germany had to agree that they were guilty for causing the Great War (World War I).  This was a deep blow to German pride.  So again, promises that appealed to German pride and hopes for their country (such as the Nazis offered) gained traction in the period between the World Wars.