Which statement about Earth's core composition is true?

Which statement about Earth's core composition is true?

• A. The core is composed of iron and copper.
• B. The core is composed of iron and nickel.
• C. The core is composed of iron and zinc.
• D. The core is composed of nickel and cobalt.

Answer: (B)

Understanding Earth's core composition hinges on what materials are dense enough to sink to the center during differentiation and what seismic data reveal. The core is primarily iron with nickel as the second most abundant metal, forming an iron-nickel alloy. Seismic studies show a very dense region with a liquid outer layer and a solid inner sphere, which fits how iron-nickel behaves under extreme pressures and temperatures and also explains the magnetic field produced by convection in the liquid outer core. Copper, zinc, or cobalt are not the main constituents of the core; they are much more common in crustal rocks and mantle materials. Geochemical and meteoritic evidence further supports iron-nickel as the dominant core composition.

Understanding Earth's core composition hinges on what materials are dense enough to sink to the center during differentiation and what seismic data reveal. The core is primarily iron with nickel as the second most abundant metal, forming an iron-nickel alloy. Seismic studies show a very dense region with a liquid outer layer and a solid inner sphere, which fits how iron-nickel behaves under extreme pressures and temperatures and also explains the magnetic field produced by convection in the liquid outer core. Copper, zinc, or cobalt are not the main constituents of the core; they are much more common in crustal rocks and mantle materials. Geochemical and meteoritic evidence further supports iron-nickel as the dominant core composition.