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.
1. independent assortment of chromosomes 2. crossing over 3. random fertilization. Source(s): describe detail 3 sources genetic variation meiosis: https://shortly.im/T6nmE. Latisha Â· 2 months ago. Thumbs up.