How have scientists divided the Earth into four shells or layers?

The correct division of the Earth into four distinct layers is based on their physical and chemical properties, primarily organized as the inner core, outer core, mantle, and crust.

The inner core is composed predominantly of solid iron and nickel due to the immense pressures found at these depths, which prevent the metal from melting despite the extremely high temperatures. Surrounding the inner core is the outer core, which is in a liquid state and also mainly consists of iron and nickel. The movement of this molten metal in the outer core is responsible for generating the Earth's magnetic field.

Above the outer core lies the mantle, a thick layer composed of silicate rocks that can flow slowly over time. This layer is crucial for tectonic movements and the heat transfer that drives geological activity like volcanic eruptions and plate tectonics. Finally, the crust, the thin, solid outer layer of the Earth, varies in depth and is where we find the continents and ocean floors.

This layering is significant not only for understanding the geological processes of the Earth but also for insights into its magnetic field dynamics, seismic activity, and overall structure. The other configurations presented do not align with the scientifically recognized order and characteristics of the Earth’s layers, which clarifies why the selection of inner core,