Here's a breakdown:

* Pollen: The male gamete (sperm) in flowering plants.

* Ovule: The female gamete (egg) in flowering plants.

* Fertilization: The process where the pollen grain reaches the ovule and the sperm inside the pollen grain fuses with the egg inside the ovule, creating a zygote.

This fertilization process is crucial for the development of seeds and ultimately, fruits in flowering plants.