-End world hunger
-End all wars/confrontations
or
-Cure/eliminate all disease/illness
Curing/eliminating all disease/illness would probably have the greatest long-term impact on the world. War will eventually happen at some point in the future and there are numerous causes of hunger that could cause it to happen again at some point. But if disease and illness are eliminated, they wouldn't return. New diseases might arise at some point but that would happen anyway.
Only the first option is feasible.
For the purposes of discussion...assume all are feasible
@cseajay Then do you mean each will end permanently or that they will be able to come back over time?
@LovinLarge ended permanently