What event provided an opportunity for colonies across the world to demand independence?

World War 2

Explanation:

The PF text book states:

"Before World War II began, much of Africa and Asia were divided into colonial territories. People in these colonies were also involved in the war...At the same time, calls for independence in colonies grew louder. As imperial powers like Great Britain, Japan, and France were occupied fighting one another, revolutionaries seized the opportunity to fight off colonial powers and liberate themselves."

Hope this helps!!