If Plessy said separate but equal, how is this different?

your list doesn't mention any of them at all.

and what does "these" mean anyway ?

world war i began in 1914, after the assassination of archduke franz ferdinand, and lasted until 1918. during the conflict, germany, austria-hungary, bulgaria and the ottoman empire (the central powers) fought against great britain, france, russia, italy, romania, japan and the united states (the allied powers). to new military technologies and the horrors of trench warfare, world war i saw unprecedented levels of carnage and destruction. by the time the war was over and the allied powers claimed victory, more than 16 million people—soldiers and civilians alike—were dead.

explanation:

d) true or false question

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