Well without full context I would assume Trench Warfare because thats what 3 1/2 of the 4 year wars where full of.
This is not History.. but I will still answer your question.
Tectonic plate interactions<span> are of three </span>different<span> basic types: Divergent boundaries are areas where </span>plates <span>move away from </span>each other<span>, forming either mid-oceanic ridges or rift valleys.</span>
Few jobs, bad living conditions, poor wage/work conditions, discrimination, etc
The two types of sources are maps and artifacts
