Choices:
a)system of military alliances that divided Europe into two camps
b) a system of peace treaties that invoked harsh penalties for aggressor nations and their allies
c) the knowledge that if any one nation declared war on another, all nations would rise against the aggressor
d) the introduction of new weapons and methods of warfare that made war hard to win
Answer: a)system of military alliances that divided Europe into two camps
These two camps were the Triple Alliance (Germany, Austria-Hungary, and Italy) and the Triple Entente (France, Great Britain and Russia). Peace wast kept in Europe because of these two camps. But in 1914, these camps also became involved in the first world war.
