Final answer:
Age patterns in the continental crust can be observed through the geologic history of different regions. Plate tectonics explains the gradual drifting of continents and the formation of mountains. Present-day plate-tectonic processes provide an analogy for understanding the past changes in the continental crust.
Step-by-step explanation:
Age patterns and analogy with present-day plate-tectonic processes suggest about the continental crust:
Age patterns in the continental crust can be observed through the geologic history of different regions. By studying the landscape, rocks, and geological features, we can identify physiographic provinces that have distinct characteristics. These differences are a result of plate tectonics, which explains the gradual drifting of continents and the formation of mountains. Present-day plate-tectonic processes, such as the motion of tectonic plates and the formation of mountain ranges, provide an analogy for understanding the past changes in the continental crust.