Final answer:
World War I transformed into a true World war through the participation of troops from around the globe, battles fought outside of Europe in territories like Africa, Asia, and the Middle East, and the effects of globalization that spread resources and personnel internationally.
Step-by-step explanation:
World War I has traditionally been seen as a largely European conflict. However, it extended into a true World war due to the involvement of nations and battles taking place beyond the European theater. For instance, hundreds of thousands of troops from the broader British Empire including India and New Zealand fought in European battles, illustrating the global scale of participation.
In addition to European fronts, combat occurred in the Middle East within the Ottoman territories, in Africa among European colonial forces, and in Asia where Japan captured the German-controlled Chinese port of Tsingtao. This demonstrates the expansive geographic scope of military engagements during World War I.