Final answer:
The subject of this question is Geography and the Earth's crust and upper mantle are part of the Earth's structure and composition.
Step-by-step explanation:
The subject of this question is Geography. The Earth's crust and upper mantle are part of the Earth's structure and composition, which is studied in the field of geography. The crust is the outermost layer of the Earth, while the upper mantle is the layer beneath the crust.