How do historians refer to independent events that occur or change and dont affect eachother ?

which statement explains one of the reasons world war 1 was so much more destructive than earlier conflicts

possible the invasion of room could have been avodiable but the people of rome were to stubboron and to wealthy the kingdoms saw them as a threat if they dialred it downa   bit ten i dont think they wouldnt failed   china was not iacvvdoaible they caused war to much and were out of hand therefor that must have happened india i dont really know it could of

the american civil war was not caused   by slavery but by economic factors.

the answer to your question is

transform it from an expensive luxury to a mid-priced good