Sea-floor spreading provides evidence for plate tectonics by showing what process?

• A. Sea-floor spreading provides evidence by showing new ocean floor is created at mid-ocean ridges
• B. Sea-floor spreading occurs due to tides
• C. Sea-floor spreading is caused by desert erosion
• D. Sea-floor spreading explains why continents drift due to winds

Answer: (A)

Sea-floor spreading shows that new ocean floor is formed at mid-ocean ridges as magma rises and solidifies, pushing existing crust away from the ridge. This process creates younger rocks at the ridges and progressively older rocks farther from them, providing direct evidence that the ocean floor is moving and that Earth's lithospheric plates are continually being created and moved apart. The other ideas don’t fit: tides don’t generate new crust, desert erosion isn’t involved in forming ocean floor, and winds don’t drive continental drift.