Does anyone know the answer it will be greatly appreciated.

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 is the main idea of this excerpt? 1.1.3

Was the civil war inevitable? could anything have been done through compromise to stop it, or did it have to happen?