Final answer:
Genetic variation in meiosis is introduced during Prophase I due to crossing over and the random alignment of chromosomes, leading to independent assortment.
Step-by-step explanation:
Genetic variation during Meiosis cell division is introduced in Prophase I. During Prophase I, one of the most critical processes for genetic variation occurs: crossing over or recombination. This is the exchange of genetic material between non-sister chromatids of homologous chromosomes. It results in new combinations of alleles across the chromosomes, leading to genetic variation in the resulting gametes. Another process that contributes to genetic variation is the random alignment of homologous chromosomes during Metaphase I, which results in independent assortment. This means that how the pairs of homologous chromosomes line up and are separated into different cells is completely random, further contributing to the uniqueness of each gamete produced.
In contrast, if we look at the processes of Meiosis II, it can be said that Meiosis II is similar to mitosis. In both, the separation of sister chromatids occurs during anaphase (anaphase of mitosis and Anaphase II of meiosis).