In this interactive activity from NOVA, explore one of the challenges that evolutionary scientists face as you attempt to classify 10 "mystery fossils." Examine the data associated with each fossil to determine the genus and species to which it belongs, or to create your own reasoned classification. Interpret the facts associated with each fossil to explain how each classification helps define a stage related to human evolution. Lastly, using data to support your claims, assemble your own theories about the stages of human evolution. The activity demonstrates where the fossil record tells a complete story, and where gaps remain.