Which of the following is NOT considered a primary mechanism of evolution?

Cloning is not considered a primary mechanism of evolution because it is a form of asexual reproduction that results in genetically identical individuals. In contrast, the primary mechanisms of evolution—natural selection, genetic drift, and mutations—involve changes in the genetic composition of populations over time which can lead to evolutionary changes.

Natural selection is the process where individuals with favorable traits are more likely to survive and reproduce, leading to an increase in those traits in the population. Genetic drift refers to random changes in allele frequencies in a population, particularly in small populations, which can result in significant evolutionary changes over time. Mutations are changes in the DNA sequence that create new genetic variations, serving as the raw material for evolution.

Cloning does not introduce new genetic variations or facilitate adaptation to changing environments, making it distinct from these primary evolutionary processes.