Final answer:
Fossils can provide evidence of variation within a species, but it can be challenging to distinguish between different species and variations within a species using only fossil evidence.
Step-by-step explanation:
Within a species, there can be variation in inherited traits. Fossils can provide evidence of this variation through the study of morphological, biochemical, and genetic traits.
These variations pose a problem because it can be difficult to distinguish between interspecific variation (differences between members of different species) and intraspecific variation (variation within a species) using only fossil evidence. This makes it challenging to accurately identify whether two fossil specimens represent different species or simply variations within the same species.
Overall, fossils can provide valuable insights into the variation within a species, but careful analysis is required to accurately interpret the findings.