Final answer:
Vascular plant spores germinate into a free-living gametophyte generation. This is part of the alternation of generations where a multicellular haploid gametophyte alternates with a multicellular diploid sporophyte.
Step-by-step explanation:
Spores produced by vascular plants germinate into a free-living gametophyte generation. During this life cycle, the sporophyte generation, which is the multicellular diploid phase, releases spores that develop into gametophytes.
In the case of seedless vascular plants, such as ferns, these spores germinate and grow into independent gametophyte plants.
These gametophytes, which are multicellular and haploid, then produce gametes by mitosis. When gametes fuse, they form a zygote, which will then develop into a new sporophyte, thus perpetuating the cycle of alternation of generations.