The correct answer is transitional.
Gerobatrachus refers to an extinct genus of amphibamid temnospondyl, which thrived in the initial Permian, that is, about 290 mya, in the region, which is now known as Baylor County, Texas. The transitional form of fossils are those that demonstrate the intermediate form between the two distinct living species, it could be in a form of an ancestor and its descendants. It is considered that the frogs and salamanders have evolved from a common ancestor of primitive amphibian tetrapod subclass known as Temnospondyli.
Biogeographical studies use information for various fields, such as evolutionary biology, geography, geology, and climate science to determine how organisms evolved through time and how the moving of tectonic plates resulting in forming continents, mountain ranges and islands has affected their distribution.
Studies in this field explain how organisms that now live on different continents are very closely related and how the flora and fauna of islands are connected to one of the closest continents etc.
Those small sections are called Genes
