Where do the homologous chromosomes in a diploid cell come from?

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.