a) much higher average densities.
b) almost the same average density, but much older, more heavily cratered surfaces.
c) much lower average densities.
d) almost the same average density, but much younger, less-‐cratered surfaces.
b) almost the same average density, but much older, more heavily cratered surfaces.
c) much lower average densities.
d) almost the same average density, but much younger, less-‐cratered surfaces.
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a) much higher average densities.