How is the United Nations another
example of the global nature of World War
2?

The United Nations (UN) was created at the end of World War II as an international peacekeeping organization and a forum for resolving conflicts between nations. The UN replaced the ineffective League of Nations, which had failed to prevent the outbreak of the Second World War.

Through The Military Expansion.

Explanation:

Rome gave the people it conquered and others a form of roman citizenship, which enabled them to become roman citizens. As well as military expansion growing and developing the economy, bringing slaves, together with resources it received from conquered lands. Which roman people used to build their city and expand vastly.