Answer:
The immediate cause of World War I that made the aforementioned items come into play (alliances, imperialism, militarism, and nationalism) was the assassination of Archduke Franz Ferdinand of Austria-Hungary. When Russia began to mobilize to defend its alliance with Serbia, Germany declared war on Russia. I hope this helps! :)
The “Captains of Industry” and the working class. The working class believes that it is being exploited by factory owners and so struggles ensue.
The United States often uses sanctions to impose a penalty on a country. This is usually the first step taken when a country upsets another country, before violence is used.