What was the biggest cause of the dust bowl?

Morning how ur day and quick question who started the civil war?

Following archduke franz ferdinand's assassination, austro-hungarian leaders: a. aided the ottoman empire in its campaign to keep serbia under its control. b. executed nearly all prominent serbs living in austria-hungary c. threatened to invade serbia if serb leaders did not agree to a set of strict demands. d.. formed an alliance with great britain to protect austria-hungary from future attacks.

How and why did british north american colonists fight a revolution to create a constitutional republic, the united states of america?