Why did trench warfare result in such horrific casualties?

Why is it useful for historians to base certain studies on the analysis of historical themes

The articles of confederation did not allow the government the power to tax or to force the states to do anything. what challenges could this cause

The directory was unsuccessful and was eventually replaced because no constitution had been created that outlined its authority. it was connected with the reign of terror. its members did not get along with napoleon. the national convention did not agree with the directory's decisions.