how do magnetic stripes of iron in ocean rock provide evidence of seafloor spreading?; which evidence originally supported hess’s idea of seafloor spreading in 1968?; which statement describes the cyclic nature of seafloor spreading ; which statement describes the relationship between seafloor spreading and continental drift?; which information did the glomar challenger study in 1968?; which concept is described in the theory proposed by hess?; which type of material becomes molten rock at subduction zones?; which statement describes the cyclic nature of seafloor spreading? brainly