Answer: Colonialism and the hopes of power.
Step-by-step explanation:
People outside of Europe were typically fighting for their monarch, like in the case of the British Empire, Germany, and France. Nations that had no ties to the war but still ended up fighting were either pulled into it by the Europeans, i.e. the United States because of the Zimmerman Telegram and the outrage over several U-boat attacks on liners that were carrying munitions but also had American citizens(i.e. the St. Lusitania), or wanted to increase their international position and influence, i.e. Japan or China.