Problem: The seafloor spreading theory proposes that new oceanic lithosphere (crust and upper mantle) is being continuously formed along the ridge system by magma rising from below, and as this occurs, the existing rocks of the seafloor move away from the ridge. Because new material is constantly being generated at ridges, old material must be destroyed somewhere else, or Earth would expand. Since Earth is ___________scientists hypothesized the ocean floor descends into the mantle at ocean trenches. Need Assignment Help?
Group of answer choices
a. expanding
b. not expanding
c. both, expanding or not expanding at different times
What if the answer is coming out incorrect for a expanding