Final answer:
Major changes in government structures and institutions during the classical age through the medieval period signaled the beginning of the modern world. These changes included the decline of feudalism, the rise of centralized nation-states, and the expansion of trade and technology.
Step-by-step explanation:
In the transition from the classical age through the medieval period, major changes in government structures and institutions signaled the beginning of the modern world. One significant change was the decline of feudalism, a political structure where landowners held power, and serfs paid rent in the form of labor. This led to increased opportunities for social mobility and the emergence of centralized monarchical bureaucracies, eroding the feudal divide. Another change was the rise of centralized nation-states, where kings became the heads of powerful countries, reducing crime and violence. Additionally, there was an expansion of trade and technology, which led to the growth of globalization and the interconnectedness of societies and economies throughout the world.