Final answer:
Meiosis results in four genetically unique haploid cells due to crossover and reduction division, a contrast to the two genetically identical diploid cells produced by mitosis.
Step-by-step explanation:
Meiosis differs from mitosis primarily in the outcome of the cellular process. While mitosis results in two genetically identical diploid cells, meiosis produces four genetically distinct haploid cells. The reduction of chromosome number by half is one of the critical distinctions between the two forms of cell division. In meiosis I, homologous chromosomes pair up and experience crossover, ultimately leading to genetic variation. This process is absent in mitosis, where sister chromatids simply replicate without such recombination. Moreover, in meiosis II, the process is somewhat similar to mitosis, but the key difference is that the cells starting meiosis II are haploid rather than diploid, as is the case directly before mitosis. This fundamental contrast lies at the heart of how meiosis introduces genetic diversity whereas mitosis serves more to maintain genetic constancy.