How does pollen that fertilizes the egg reach the ovule?

Some of the pollen grains carried by wind,insects,birds or bats may reach a carpel and stick to the ripe stigma.Each pollen grain produces a tiny tube which grows down to the style,into the ovary and towards the ovules or egg cells.when one of the tubes reaches an ovule,it bursts open.A male nucleus from the pollen grain then moves down the pollen tube to join with the nucleus of the female sex cell,the ovule.when the nuclei of the pollen grains and ovules have joined together, the ovules are said to be fertilized.