1.   Casts were made for these sculpted bones, just as they were with the actual fossils, for shipment to Atlanta.

2.   Even if life did evolve on Mars, some researchers think our prospects of finding actual fossils are slim.

3.   Life-size bone models were cast, when possible, from actual fossils in Argentina.

4.   Mounting actual fossils can cause them to crack and bend.

5.   The discovery did not include any actual fossils.