Cause:Over the course of the 19th century, rival powers of Europe formed alliances. Germany, Austria-Hungary, and Italy formed the Triple Alliance. Great Britain, France, and Russia formed theTriple Entente. Political instability and competition threatened those alliances. (Italy, for example, eventually entered World War I in opposition to Germany and Austria-Hungary.)
Effect:As many as 8.5 million soldiers and some 13 million civilians died during World War I.
Hope it helped~Hannah
