What is the role of pollen grains in the fertilization process of flowering plants?

Pollen grains play a crucial role in the fertilization process of flowering plants by carrying male gametes to the ovule. When a flower is pollinated, pollen grains are transferred from the male anther of the stamen to the female stigma of the pistil. Each pollen grain contains sperm cells and, upon landing on the stigma, it germinates and forms a pollen tube that grows down the style towards the ovule. This process allows the sperm to reach the ovule, where fertilization occurs, leading to the formation of seeds. This mechanism is vital for sexual reproduction in flowering plants and ensures genetic diversity within plant populations. The other options do not accurately reflect the role of pollen grains in this context.