Final answer:
The trends affecting countries' abilities to fight in World War I include changes in industrialization, military stockpiling, alliances, and financial policies. These factors dictated how prepared a nation was for war, its ability to sustain military operations, and the role it played in the conflict. Domestic and international politics also influenced nations' abilities to mobilize for and conduct war effectively.
Step-by-step explanation:
The impact of various trends on a country's ability to fight in World War I correlates with the nation's military and economic changes during that time. Dramatic changes in a nation's industrial capacity, military stockpiling, and alliances would significantly affect their role in the war. An increase in industrialization allowed countries to produce more modern weapons and amass larger armies, thereby increasing their warfighting capabilities. Alliances made through treaties obligated countries to support one another, which meant that any conflict could potentially escalate into a broader war. For example, the intricate network of alliances is why the assassination of Archduke Franz Ferdinand of Austria-Hungary led to a world war.
Furthermore, the financial tariffs and taxes imposed could affect a country's economy and thus influence its ability to sustain a long-term conflict, like WWI. Countries that experienced economic hardship would struggle to support their troops and maintain war supplies. Likewise, social factors, such as opposition from socialists and other political groups, could undermine a nation's war efforts, as seen in Britain where socialist leaders organized opposition to the war. Lastly, the isolationist policies and internal conflicts within countries, such as the Irish seeking independence from Britain and the rise of Nazism in Germany post-war, show how the political landscape can dictate a country's stance and involvement in international conflicts.