WILL MARK BRAINLIEST IF CORRECT Which concept is described in the theory proposed by Hess?

Continents do not move.
Cool rock pushes through the crust.
Trenches are sites of seafloor spreading.
Mid-ocean ridges are sites of seafloor spreading.

Mid Ocean ridges are sites of seafloor spreading.

Explanation: In 1960, he proposed a  theory which is later became known as 'Sea Floor Spreading'. Hess discovered that the oceans were shallower in the middle.  According to Hess, From Earth’s mantle molten material is  continuously flowing along the crests of the mid-ocean ridges.

As soon as temperature of  magma decreases, it is pushed away from the flanks of the ridges. Due to this process a younger ocean floor is created.

Hess also proposed that due to light weight of continental crust, it didn't sink back into the deep earth at trenches as did the oceanic crust.

D)  Mid-ocean ridges are sites of seafloor spreading.

Explanation:

answer called a epicycle;