Answers:
Allow me to add a bit of explanation about the last item, the Schlieffen Plan.
The military plans laid before World War I presupposed a major war between the countries which were tied together with alliances. Because the Triple Entente had Britain, France and Russia as allies, Germany thought if a war began it would need to fight on two fronts -- west and east. So German Field Marshall Alfred von Schlieffen drew up war plans that said attack France first, quickly, and then hold that territory while deploying forces to contend with Russia in the east. So when Germany declared war on Russia in 1914, the first thing it did was to march through Belgium to go and attack France. Thus the war spread and became instantly a more global conflict.