Due to the changes in existing environmental conditions, the individuals of a population may undergo modifications to enhance their survival. This results in the appearance of different characters (homologous organs) and different species from a common ancestor. This type of evolution is called divergent evolution.
A. Adaptive radiation is the differential development of adaptations in a group of organism, such that they evolve into different species, each capable of surviving in different environments.
B. Uniformitarianism is a theory that suggests gradual changes in earth's crust due to steady geological processes.
C. Catastrophism suggests violent processes for the changes on earth.
D. Convergent evolution results in the appearance of similar characters (analogous organs) due to the similarity in the habitats of two different species.
Hence, the correct answer is 'Adaptive Radiation'.