Final answer:
Fred Vine and D.H. Mathews related the seafloor-spreading hypothesis to magnetic reversals by studying the magnetization of rocks on the seafloor at mid-ocean ridges.
Step-by-step explanation:
Fred Vine and D.H. Matthews related the seafloor-spreading hypothesis to magnetic reversals through their research in the 1960s.
They discovered that as new oceanic crust is formed at mid-ocean ridges, it carries with it magnetic minerals that align with the Earth's magnetic field. This alignment is preserved in the rocks as they cool and solidify. Through this process, Vine and Matthews found that the magnetization of rocks on the seafloor reverses in a coordinated manner with distance from the ridge.
They concluded that these magnetic reversals could provide a historical record of the Earth's magnetic field over time.