Answer: In 1917, Germany, determined to win its war of attrition against the Allies, announced the resumption of unrestricted warfare in war-zone waters. Three days later, the United States broke diplomatic relations with Germany, and just hours after that the American liner Housatonic was sunk by a German U-boat.
The correct answer is A) Johanan Ben Zakkai. Hope this helps.
"Surrogate wars" also known as "proxy wars" are wars fought in a third country. The US and the Soviet Union were fighting each other in, for example, Afghanistan and Vietnam.
They preferred proxy wars, because they came without civilian victims of own population and without a distraction of the infrastructure of their own countries. In short, the two powers could compete militarily with each other without suffering the worst effects of the wars - this situation allowed them to try to defeat the other one without much risk to their own population.
Southern Secession is the event or issue that historians can gain.
