After the Spanish-American war, the US controlled Puerto Rico, the Philippines, and Guam.
The Allied faction, most notably the British, has gained the upper hand during the first world war due to their acquisition of various oil fields. The oil has powered their military vehicles most notably its naval fleet and the introduction of Mark V tanks that posed significant advantage at the course of the war.
I think that the Answer: is a
Explanation:
The idea that a country or region should specialise in making and exporting goods and services that it can produce most efficiently.
