Final answer:
Meiosis, particularly meiosis I, introduces the greatest amount of genetic variation through processes such as crossover where homologous chromosomes exchange parts, creating new gene combinations in gametes.
Step-by-step explanation:
The type of cellular division that accounts for the greatest amount of genetic variation is meiosis. During meiosis, specifically in meiosis I, homologous chromosomes pair up and undergo crossover, where they exchange non-sister chromatid segments. This creates new combinations of genes in the resulting gametes. Consequently, when fertilization occurs, it combines the diverse genetic material from two parents, further increasing genetic variation. In contrast, mitosis and cytokinesis result in daughter cells with identical genetic material to the parent cell, therefore not contributing to genetic variation in this way.
Meiosis II is similar to mitosis in that sister chromatids are separated, much like how mitosis operates. However, due to the previous crossover event in meiosis I, the resulting daughter cells from meiosis are not genetically identical, unlike the outcome of mitosis.