Final answer:
The eastern margin of North America changed from an active margin to a passive one after the Paleozoic era.
Step-by-step explanation:
The statement is true.
The eastern margin of North America changed from an active margin to a passive one after the Paleozoic era. During the Paleozoic era, North America was tectonically active, with tectonic events such as the collision of Euramerica (or Laurussia) with Gondwana forming the Appalachian orogeny.
However, in the Mesozoic era, Pangaea started to break apart and the eastern edge of North America became tectonically inactive, resulting in a transition from an active margin to a passive one.