This figure shows a mid-ocean ridge. drag words to complete the sentences. large allow blocks of crust to be displaced downward, forming a rift. basaltic lava erupts within the rift forming on the seafloor. other magma solidifies within fissures, forming as the crust cools, it subsides and is covered by which tends to smooth over any rough topography. as two oceanic plates move apart, rock and magma in the rise to occupy this space.