Aid is when supplies to help from other country that supplies food, medicine and etc.
Treaty is a formally concluded and ratified agreement between countries.
Alliances is a union or association formed for mutual benefit, especially between countries or organizations.
The U.S. is not in the diagram because maybe during that time U.S. doesn't involved in that countries. But, later on U.S. get involved in the diagram because of the WW1. They join in the diagram because they in some point to help give some aid to people that is sick for medicine and food.
Treaty is a formally concluded and ratified agreement between countries.
Alliances is a union or association formed for mutual benefit, especially between countries or organizations.
The U.S. is not in the diagram because maybe during that time U.S. doesn't involved in that countries. But, later on U.S. get involved in the diagram because of the WW1. They join in the diagram because they in some point to help give some aid to people that is sick for medicine and food.