Which nation was hit hardest and suffered the loss of over 20 million lives?

Russia

Explanation:

Russia was the most effected nation that saw the devastating deaths of about 20 million people in the world war II both the military and the civilians. The Russians military (Red Army) underwent a disastrous death of men during the first months of the German invasion, with capturing large numbers of Soviet soldiers and civilians as laborers under ruthless circumstances. The fighting damaged farming land, towns, leaving much of the people homeless and without food.

federal power is further limited with a system of checks and balances that gives each branch of government a measure of power over the others.

explanation:

in 1897, pershing became a tactical officer at west point, and that's where he was given the nickname "black jack." pershing's first name is "john," for which "jack" is a nickname, and he was a white man who commanded black troops. hence "black jack".