Question

what observation did alfred wegener make that led him to develop the theory of continental drift? the seafloor has \magnetic stripes\. continents appear to have once fit together. earths magnetic poles have reversed polarity in geologic history. the ocean floor has long ridges of volcanic mountains.

Explanation:

Alfred Wegener noticed that the continents' shapes seem to fit together like pieces of a jigsaw - puzzle, which was a key observation for his continental - drift theory. The other options are related to different geological and geophysical concepts not directly associated with his initial inspiration for continental drift.

Answer:

Continents appear to have once fit together.