how was the nature of the conflict during world war I and World War II?

Question

also what was the size of the conflict

Answer 1

World War I was typified by static defences, at least in Europe. That is a line of trenches from the English Channel to Switzerland and across the north of Italy. There was not much movement.

In WW II was typically highly mobile, using armour and mechanised infantry to cover large distances comparatively quickly. The blitzkrieg in France in 1940, and the vast tank battles of the Russian Front.

In the Pacific in WW II the naval tactics involved air power, and a series of amphibious landings.