Bodies of water, specifically rivers.
Some effects are:
<span>- A new republic in France </span>
<span>- the fall of Metternich </span>
<span>- promises of reform in Austria, Italy, and Prussia </span>
<span>- A new empire established in France </span>
<span>- Success in liberalism, nationalism, and socialism </span>
The direct cause of WWI was the assassination of Archduke Franz Ferdinand at Sarajevo on 28 June 1914. However historians feel that a number of factors contributed to the rivalry between the Great powers that allowed war on such a wide-scale to break out.
It’s letter c for the answer of this question