Answer:
A. fossil evidence
Step-by-step explanation:
Scientists have found fossil evidence that ancient whale like creatures have legs.
It is through fossil evidence alone that we can know what ancient life forms are compared to their present day living forms.
- A fossil is a preserved remain of parts of a dead and ancient organism.
- Fossil remains are usually found in sedimentary rock strata where they are preserved.
- A whole organism can be preserved but this is a rare case.
- Most times, the hard parts of an organism are the most common fossils.