Evidence of seafloor spreading and plate movement strengthened which understanding in geography?

Correct answer: Earth's surface changes over time

The direct answer is A: evidence of seafloor spreading and plate movement strengthened the understanding that Earth’s surface changes over time. To understand this, remember that the lithosphere is broken into plates. At mid-ocean ridges, magma rises, cools and forms new oceanic crust. This new crust moves away from the ridge, while older crust may be recycled at subduction zones. Thus continents and ocean basins are not permanently fixed; they change over very long geological periods. Option A is correct because it describes a dynamic Earth. Option B is wrong because the evidence directly contradicts the idea of a completely fixed surface. Option C is wrong because oceans are central to the study of seafloor spreading and are an important part of geography. Option D is wrong because continents do not float in air; they move as parts of solid tectonic plates over the weaker asthenosphere. The movement is slow, usually only a few centimetres per year, but its effects become large over millions of years. Exam cue: seafloor spreading means new crust and a changing Earth.