By which number -7 /25 should be divided to get -1/15?

21/5

Step-by-step explanation:

if a/b = c, then b=a/c

in other words:

divide -7/25 by -1/15 to get the answer

It also helps to use the fact that a/b / c/d = a/b * d/c

-7/25 / -1/15 = -7/25 * -15/1

= 105 / 25

= 21 / 5

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.