Question

harry hesss discovery of seafloor spreading helped to support the continental drift hypothesis because it
o illustrated how the coastlines of continents fit together like pieces of a puzzle
o proved that convection currents exist in the mantle
o showed that sections of crust could drift apart as the seafloor spread

Explanation:

Harry Hess's seafloor spreading theory proposed that new oceanic crust is formed at mid - ocean ridges and moves away from them. This movement of the seafloor causes the continental crust (which is less dense and 'floats' on the mantle) to drift apart. The other options are incorrect: Wegener (not Hess) used the puzzle - like fit of continents; the existence of convection currents in the mantle was a concept related to the mechanism of plate movement but Hess's key contribution was showing the link between seafloor spreading and continental drift; and Hess's work was more about the dynamic process of crustal movement rather than just proving convection current existence.

Answer:

showed that sections of crust could drift apart as the seafloor spread