Find the missing number please

answer:

explanation:

let small figure A = 100

figure B obtained by increasing A by 25%.

so figure B=125

figure B is decreased for figure A =  = 20%

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.