Answer:
A. Speciation
Step-by-step explanation:
The adaptive radiation can simply be defined as rapid diversification, or speciation, of one ancestral species, to numerous different species. This happens mostly as a result of ecological opportunities. Practically. when there are numerous niches free in an ecological system, one species will start to diverge into numerous other species if it has the opportunity. Groups of the species will start to adapt to certain niche that is free, thus developing their own unique traits, gradually becoming distinct enough that they create another species.