Final answer:
Evolution is the correct answer, as it refers to a change in gene frequencies over time in a population. This change can be driven by genetic drift, natural selection, mutations, and gene flow, all of which contribute to the evolutionary process.
Step-by-step explanation:
The change of gene frequencies over time in a population of organisms is referred to as evolution. This process is driven by mechanisms like genetic drift, natural selection, mutation, and gene flow. Evolution is defined as a change in the frequency of an allele within a population, such as changes observed in the ABO blood type allele frequencies. If the change is advantageous, it may become more common due to natural selection.
Genetic drift is a random fluctuation in allele frequencies that occurs by chance. For example, this can happen when some individuals have more offspring purely due to chance events, rather than because they possess advantageous traits. Mutations introduce new genetic variations, which can also lead to changes in allele frequencies over time when these mutations provide some benefit or are neutral but become common due to random factors.