Which event in 1917 caused the united states to enter world war 1 check all that apply

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

This map shows north korea and south korea today. how does this map reflect the impact of the korean war?

Based on the information given and the gauges which process or processes have their alarm light on?