One of the cells in the embryo sac has 2 separate polar nuclei. Pollen sacs have diploid microsporocytes. Meiosis produces haploid microspores. Microspore mitosis produces male gametophyte, the pollen grain, with a tube cell and generative cell. Generative cell will divide into 2 nonmotile sperm.
Pollination is transfer of pollen grains from anther to stigma.
Self pollinated if pollination of same flower or another flower on same plant Cross pollinated if pollen goes to flower on another plant. Insects, other animals like birds, wind. Flowers want to attract animal pollinators with visually showy petals or scent. Insects see UV radiation, and some flowers have UV bullseye. Birds like hummingbirds see red, orange, yellow, no strong scent.