Great Migration: Life for Migrants in the City. By the end of 1919, some 1 million blacks had left the South, usually traveling by train, boat or bus; a smaller number had automobiles or even horse-drawn carts.
Genetic variation is increased by meiosis During fertilisation, 1 gamete from each parent combines to form a zygote. Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA.
Independent assortment in meiosis, describes how each pair of homologous chromosomes segregates independently of other pairs, such that maternally and paternally inherited chromosomes are distributed randomly into gametes, leading to greater genetic possibility in fertilized offspring.