Final answer:
The evidence that supports the theory of seafloor spreading is the movement of tectonic plates apart at a divergent boundary at the mid-ocean ridge, which aligns with Wegener's continental drift hypothesis.
Step-by-step explanation:
The theory of seafloor spreading provides evidence that supports the larger theory of plate tectonics. Among the provided options, the one that directly supports the concept of seafloor spreading is 'Tectonic plates move apart at a divergent boundary located at the mid-ocean ridge'. This is because as tectonic plates diverge, molten rock from the mantle rises up and solidifies to form new ocean floor at mid-ocean ridges, which is the essence of seafloor spreading. Additionally, the symmetrical pattern of magnetic stripes on the ocean floor is a key piece of evidence, showing that the Earth's magnetic field has reversed many times, which aligns with new crust being formed continuously over geological time periods.
Alfred Wegener's continental drift hypothesis, proposed in 1915, suggested that continents once formed a giant supercontinent called Pangea, based on evidence like the puzzle-like fit of continents and fossils of the same plants and animals found on different continents. Seafloor spreading is one of the key mechanisms that caused the drifting of continents, expanding on Wegener's original idea and providing a dynamic picture of earth science.
When studying the mid-Atlantic ridge, scientists observe volcanic activity that contributes to the formation of new seafloor. This also links to the concept of magnetic reversals, where rocks' magnetization patterns provide a historical record of Earth's magnetic field reversals, further proving that new seafloor has been created over time and has spread outward from the ridge.