Final answer:
The subject of this question is Geography. Loose dirt refers to the top layer of soil that can easily be removed or disturbed. This is related to the study of soil composition and landforms in Geography.
Step-by-step explanation:
The subject of this question is Geography. Loose dirt refers to the top layer of soil that can easily be removed or disturbed. In the given context, the loose dirt is being described on the surface of the planet Eros, with a layer of surface rubble and scattered boulders. This is related to the study of soil composition and landforms in Geography.