What happened in Europe that caused the development of individual kingdoms and city-states during the Middle Ages?

What did europeans build much of during the eleventh and twelfth centuries? ?

How were japan's actions before and during world war 2 compare with germany's actions over the same period

What were the purposes of salt? check all of the boxes that apply. -to achieve peace -to protect the security of the united states -to form an alliance against communist nations - to stop the nuclear arms race - to give the united states an advantage over the soviet union