Answer:
The true statement among the options provided is:
A. Seafloor spreading causes continents to move apart; subduction brings them together.
Step-by-step explanation:
Why?
Seafloor spreading is a geological process that occurs at mid-ocean ridges, where new oceanic crust is formed and pushes the existing crust apart. This movement of the seafloor causes continents to move apart. On the other hand, subduction occurs when one tectonic plate is forced beneath another, typically at convergent plate boundaries. Subduction brings the tectonic plates together and can result in the collision and uplift of continental crust.
Why Option B, C, and D are incorrect:
Option B is incorrect because the amount of seafloor spreading does not need to be greater than the amount of subduction to keep the Earth's surface area constant. The overall balance of seafloor spreading and subduction maintains a relatively constant surface area of the Earth.
Option C is incorrect because seafloor spreading actually leads to the widening of ocean basins, not their narrowing. As new crust is created at mid-ocean ridges, it pushes the existing crust apart and results in the expansion of the ocean basins.
Option D is incorrect because subduction is the process through which oceanic crust is consumed by sinking beneath another tectonic plate. It does not create ocean floor; rather, it plays a role in the recycling and destruction of oceanic crust.