Detailed Instructions: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Q: People can learn about these specimens through their current physical state, called?, Context: The oldest known fossil among the Eutheria ("true beasts") is the small shrewlike Juramaia sinensis, or "Jurassic mother from China", dated to 160 million years ago in the Late Jurassic. A later eutherian, Eomaia, dated to 125 million years ago in the Early Cretaceous, possessed some features in common with the marsupials but not with the placentals, evidence that these features were present in the last common ancestor of the two groups but were later lost in the placental lineage. In particular:
A:
fossil