Harry Hess and Robert Dietz proposed that the oceanic crust in the Atlantic Ocean was spreading apart at the Mid-Atlantic Ridge and that this process moved the continents apart from one another. They called this process:

A) seafloor spreading
B) continental drift
C) plate tectonics
D) Gondwana

Seafloor Spreading

The process by which new oceanic crust is formed at mid-ocean ridges and slowly moves away from the ridge, contributing to continental drift.

Continental Drift

The theory that Earth's continents have moved over geologic time relative to each other, thus appearing to drift across the ocean bed.

Mid-Atlantic Ridge

A continuous underwater mountain range in the Atlantic Ocean, formed by tectonic plate divergence.