The Fossils of a New Species of Reptile Are Found

The fossils of a new species of reptile are found in deposits dating to the Permian period. Later, scientists discover that fossils of the species changed somewhat over time and can be found in deposits dating from the Permian period all the way up to the Cretaceous period. The fossils vary from one continent to another, but many seemingly intermediate forms are found, and the fossils are spread over most continents. The scientists' observations most strongly support which evolutionary models) ?

A) allopatric speciation
B) punctuated evolution
C) adaptive radiation
D) both allopatric speciation and adaptive radiation
E) gradualistic evolution The observations that the fossils are found on most continents and that they have changed over long periods of time suggest the gradualistic model of evolution. The spread of the fossils over multiple continents also suggests that speciation occurred in the Permian period, when the continents were joined together, and that a slow, gradual evolution occurred while the continents separated, throughout the Paleozoic and Mesozoic eras. The observation that many intermediate forms are found suggests that all of the fossils belong to the same species because significant amounts of interbreeding between populations probably occurred.