The First World War is associated with each of the events mentioned. Secret alliances formed the ‘who vs. who’ during the war. The assassination of the Archduke triggered the beginning of the war. Stalemate along the trenches describes the deadlock that often took place during the war because of the trench warfare. Neither side could definitively win a battle swiftly at times because both armies remained near their trenches. Hope this helps :) (Brainliest please?)
