What potential information might a long-preserved Martian artifact retain that a skeleton decades old on Earth might lack?

Answer

Protein structure or even heavily damaged DNA fragments.

Due to the stasis provided by cold and dryness (despite radiation damage), soft tissue remnants may remain recognizable and retain molecular remnants for extremely long periods.

What potential information might a long-preserved Martian artifact retain that a skeleton decades old on Earth might lack?
MarsSpacedecompositionbodyastrobiology