Final answer:
Scientists initially didn't accept Wegener's Continental Drift hypothesis because he lacked a clear mechanism to explain continent movement.
Step-by-step explanation:
Wegener's suggestion was met with skepticism from scientists because he was missing a clear mechanism to explain how continents could drift over thousands of miles.
Many scientists found the idea of moving continents too revolutionary to take seriously. However, once the evidence and mechanism (plate tectonics) became clear, Wegener's hypothesis gained acceptance and became central to our understanding of Earth's dynamics.