Why was WW1 different from wars that preceded it?

Many people say submarines and machineguns, however Holland submarines were in the Russian & Japanese inventories during the Russo-Japanese War of 1904-05; and machineguns were heavily used during that 1904 war Although submarines did make their debut in mass service in WWI, no preceding war can take credit for using mass amounts of chemical warfare & airplanes as WWI can.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.