Which is the innermost layer of the Earth?

Which is the innermost layer of the Earth?

• A. Inner core
• B. Outer core
• C. Mantle
• D. Crust

Answer: (A)

Earth's interior is layered, and the deepest zone is a solid sphere at the center. Surrounding it is a liquid layer, then a thick mantle, and finally the crust. The center stays solid because the immense pressure there keeps iron-nickel from melting, even though temperatures are extremely high. Seismic waves help reveal this structure: some waves cannot travel through liquids, showing the presence of the liquid outer layer, while the way waves slow and bend at boundaries indicates a distinct solid core inside. So the innermost layer is the solid inner core.

Earth's interior is layered, and the deepest zone is a solid sphere at the center. Surrounding it is a liquid layer, then a thick mantle, and finally the crust. The center stays solid because the immense pressure there keeps iron-nickel from melting, even though temperatures are extremely high. Seismic waves help reveal this structure: some waves cannot travel through liquids, showing the presence of the liquid outer layer, while the way waves slow and bend at boundaries indicates a distinct solid core inside. So the innermost layer is the solid inner core.