Answer: A.Transitional forms show the evolutionary steps between species.
Fossils are dead remains. Organisms leave imprints upon death and these imprints are preserved in sedimentary rock. A transitional fossil, however, is any fossil of a life form capable of exhibiting common traits between an ancestral group as well as its derived descendant group. These fossils are important as a result of their ability to demonstrate the evolutionary changes occurring between organisms. This can help in displaying seemingly intermediate traits between a common ancestor and all of its descendants.