Because economy within a certain region will be heavily depended on what resources that are available in that region.
Since the Arabian Pennisula do not possess a good climate to produce agricultural products, it's almost impossible for agricultural sector to flourish in this region, and therefore they focused their economy on things such as oil, silk, zaitun, etc.
An increase in military spending is most likely caused by war, or multiple wars, or incoming wars, or similar.
The Genetic Information Nondiscrimination Act of 2008.
Rivalry
Colonial and imperialistic ambitions was a major contributor of rivalry and hostility that beheld western Europe in the decades before ww1. Each of the nations was seeking to out do each in strategic colonies such as Egypt, east africa,India and some provinces in Europe such as Alasce and Lorraine.
The Tulsa race riot of 1921. It happened between may 31 and june 1.
