Answer;
Meiosis and fertilization;
Meiosis and fertilization are the processes that lead to the greatest variety of genetic combinations
Explanation;
Meiosis is the type of cell division that produces the gamete cells (eggs and sperms). The process involves division of a parent cell into four daughter cells that are haploid and different from the parent.
It involves cross over and genetic recombination through the exchange of genetic materials between homologous chromosomes which creates genetic diversity.
Fertilization is the process of fusion between male and female gametes; which are haploids and therefore joins to form a diploid zygote and this ensures genetic variation to the fetus as it has received genetic material from two parents.