What is the principle of federalism?

Which four of these developments were made under mongol rule during the pax mongolica? the extension of the grand canal in china the spread of christianity the spread of weapons that used gun powder the invention of new medicines the establishment of a postal system the invention of geometric models of lunar motion

Iron making developed in china almost a thousand years later than in the middle east. true false

Which of these actions were taken by the us government to get ready for war? check all that apply. using a draft to build armed forces planting victory gardens for food and to boost morale promoting conservation of key products trying to get people to buy liberty bonds taking new jobs to meet demands promoting patriotism