How many solutions does a two distinct concentric circles have

Two distinct concentric circles never intersects each other . Hence it does not have any solutions. As we know that the two parabolas intersect at a maximum of Two Points.

the answer is; biodiversity resulting from few ancestors

adaptive radiation occurs when a population is subjected to a large natural environment with spatial ecological variations. the parts of the population in the different ecologies begin to adapt to their local environments. due to non-random mating across the large populations, this causes the different populations from the large population to speciate within their local environments. they, therefore, diverge to different species sharing a common ancestor.