(A) policies of isolation
(B) international organizations
(C) ** systems of alliances
(D) policies of appeasement
EXPLANATIONS BELOW
Concept note-1: -Answer and Explanation: European nations formed alliances with other European nations during the early 1900s in order to prevent themselves from being attacked. The most notable example of this was the Triple Entente formed between the Untied Kingdom, France and Russia.
Concept note-2: -Forces and resources of the combatant nations in 1914. When war broke out, the Allied powers possessed greater overall demographic, industrial, and military resources than the Central Powers and enjoyed easier access to the oceans for trade with neutral countries, particularly with the United States.
Concept note-3: -By 1914, Europe’s six major powers were split into two alliances that would form the warring sides in World War I. Britain, France, and Russia formed the Triple Entente, while Germany, Austria-Hungary, and Italy joined in the Triple Alliance.
Concept note-4: -How was peace kept in Europe until 1914 despite the rapid buildup of armies and weapons? Through a system of military alliances that divided Europe into two camps.