In this triangle, D is the midpoint of AB and E is the midpoint of BCIf AC = 36 what is the length of DE?

A. 18

Step-by-step explanation:

Recall: the Mid-segment Theorem states that the length of the mid-segment theorem of a triangle is half the length of its third side.

DE = ½(AC) (Triangle Mid-segment Theorem)

AC = 36 (given)

Plug in the value

DE = ½(36)

DE = 18

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.  

just sum

10 + 10 = 20