Answer: The answer is natural selection
Explanation:
Natural selection explains how certain desirable traits like;
- shape of the beaks of Darwin's finches: to help them feed more easily
- industrial melanism to raise a population of dark-coloured organisms to evolve from pre-existing light coloured ones in industrial areas where the surrondings are blackened with soot;
are favored over LESS DESIRABLE TRAITS, resulting in organisms that are most suited/adapted to thrive in an environment, which is evolutionary change
When humans farm large plantation of one cash crop, they reduce the biodiversity of the region because they reduce the genetic diversity of the species in the environment. A reduction in genetic diversity means that the genetic variability of the species is reduced hence there are fewer sub-species in the environment. This ultimately reduces the biodiversity of the ecosystem - which is the variability among all the living organisms in the environment.
From the deepest to most superficial: pia mater, arahnoid, dura mater