Does anyone know the timeline for this?

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

What were the main features of the aristotelian-ptolemaic model of the cosmos

List two inventions that were invented in the united states before the american civil war