Answer:
Natural Selection
Consistently causes a population to become better adapted to its environment
A result of differential success in reproduction
Cannot cause a harmful allele to become more common
Genetic Drift
Responsible for the founder effect
Responsible for the bottleneck effect
Causes allele frequencies to fluctuate randomly
Gene flow
Can introduce new alleles into a population's gene pool
A result of the movement of fertile individuals or their gametes
Explanation:
From the above the mechanisms of evolution have each been matched to their definitions and characteristics. Notable is natural selection which is the central concept of evolution whereby organisms become better adapted to their environment with more tendency to survive and produce offspring who continue in this manner. It stems from the theory of evolution by Charles Darwin, and now regarded as the main process that brings about evolution