Mantle is the layer that is defined by its chemical composition.
The layer of the chemical composition of the Earth from within to outside includes core, mantle and crust.
- The Core is the innermost structure of the earth and regarded as the hottest part of the earth.
- The mantle constitute the lithosphere and the inner part of the earth outside its core boundary.
- The crust is the surface of the earth planet which can be identified from space.
Therefore, the answer is D. because it is the layer that is defined by its chemical composition.
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