Adaptive radiation refers to the evolutionary process in which a single ancestral species diversifies into multiple different species, each uniquely adapted to occupy specific ecological niches or habitats. This diversification leads to the emergence of various new species that are well-suited or adapted to exploit different environmental conditions, resources, or ecological roles.

Among the options provided, the most accurate description of adaptive radiation is:

Evolution of different species from a common ancestor.

Geographical isolation or migration can be factors that contribute to the initiation of adaptive radiation by creating opportunities for populations to diverge and evolve different adaptations in response to local conditions. Darwin’s finches represent one of the best examples of this phenomenon. Another example is Australian marsupials.