Here's a breakdown:

* Spores: These are single-celled reproductive units that are produced in structures called sporangia located on the underside of fern fronds.

* Sporophyte Generation: The fern plant you typically see is the sporophyte generation, the dominant phase in the fern's life cycle. It produces spores.

* Gametophyte Generation: When a spore lands in a suitable environment, it germinates and develops into a small, heart-shaped structure called a gametophyte.

* Gametes: The gametophyte produces both male and female gametes (sperm and egg) through mitosis.

* Fertilization: Sperm from one gametophyte fertilizes an egg from another gametophyte, forming a zygote.

* New Sporophyte: The zygote develops into a new sporophyte, completing the life cycle.

So, while ferns don't have specialized cells like eggs and sperm in the same way that animals do, they use spores, which are single-celled units that give rise to the gametophyte generation, which ultimately produces the gametes for fertilization.