Scientists were able to map the ocean floor using two devices namely (a). and magnetometers attached to battle ships during the World War II. Magnetometer discovered an astonishing feature in the ocean floor. The ocean floor rocks show a pattern of normal and reversed (b) polarity. Alternating stripes of normal and reverse polarity were observed in the ocean floor rocks. The earth's lithosphere is broken into minor and major chunks of rocks called plates. Mantle (c). happen when the earth's interior, the inner core, heat the mantle materials below. There are two other driving forces that explains the movement of earth's plates. These are (e). and slab pull. There are other two theories which attempted to explain the possible cause of earth's plate movement namely (h). and Seafloor spreading. According to Alfred Wegener, Earth's continents were once connected as a single, massive supercontinent called (i). where he studied on three (3) things to support his claimed on his theory specifically on fossils, rocks and fit of continents. Meanwhile, Seafloor spreading theory, proposed by U) attempted to provide the missing mechanism in Wegener's Continental Drift theory. He explained that formation of new seafloor causes the movement of the earth's plates.

Alfred Wegener

echosounders

continental drift theory.

convection

Harry Hess.

magnetic

Pangaea

ridge push
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