Answer:
The phylogenetic species concept.
Step-by-step explanation:
The biological species concept states that a species is a group of individuals that can breed together, that is a group of individuals reproductively isolated from other groups of individuals. According to this concept it is impossible to classify fossils since fossils are just traces of any once-living organism (no longer alive). However in order to classify taxonomically fossils , the phylogenetic species concept can be used.
The phylogenetic species concept, which is not based on breeding but in evolutionary relationships. If a fossil group share a common ancestor and are evolutionarily distinct from all other groups, the group then recognized as a species. Morphological and / or genetic analysis of fossils are used to determine the evolutionary relationships and establish if te group is or is not a species.