Notice the population of beetles. the allele for color is seen on their backs: green and brown alleles. over time, through random chance, the gene pool of the beetle population changes. eventually the gene pool contains only green alleles. this is an example of
a) gene flow.
b) adaptation.
c) genetic drift.
d) natural selection.

C) genetic drift.

Explanation:

Genetic drift is a process of random change in the allelic frequencies of a population. Genetic drift is a stochastic process and it is impossible to predict the direction of change. This means that changes occur at random and not by adaptation to the environment.

In its simplest terms, genetic drift is just a random change in the genetic makeup of a population over time. This population had some characteristics that were modified, causing the population to start to present other characteristics. An example of this can be seen in the question above, where a population of beetles that were green and brown began to turn green only, over time. This change came about at random, meaning genetic drift occurred.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation