Answer please i will give brainliest

Step-by-step explanation:

a.

simply add both equations

x + y = 2

-3x - y = 5

-2x + 0 = 7

x = -7/2

x + y = 2

-7/2 + y = 2

y = 2 + 7/2 = 4/2 + 7/2 = 11/2

b.

1/2 x + 2y = -13

x - 4y = 8

first multiply the first equating by 2

x + 4y = -26

x - 4y = 8

2x + 0 = -18

x = -18/2 = -9

x - 4y = 8

-9 - 4y = 8

-4y = 17

y = -17/4

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.  

answer: 5

step-by-step explanation: