Which one of the following generates new genetic combinations leading to variation?

Explanation

Sexual reproduction involves the formation and fusion of male and female gametes. Gamete formation is accomplished through meiotic cell division which involves crossing over between non­sister chromatids of homologous chromosomes leading to new genetic recombination in gametes. Random fusion of these male and female gametes leads to genetic variability in the offspring which although resemble their parents also exhibit new traits of their own. Vegetative propagation is a type of asexual reproduction that produces progeny by any vegetative propagule (rhizome, tubers, suckers, etc.) without gamete formation and fertilization of male and female gametes. Parthenogenesis is a natural form of asexual reproduction in which the growth and development of embryos occur without fertilization by sperm and only an egg(female gamete) is required. The occurrence of more than one embryo in a seed is referred to as polyembryony.