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Gymnosperms
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The gametophyte is not an independent, free-living generation in$Pinus$ is a gymnosperm. In gymnosperms the male and female gametophytes do not have an independent, free-living existence.
The male gametophyte is confined to the pollen grain and the female gametophyte is retained within the megasporangium (ovule) on the sporophyte.
$Polytrichum$ (a moss) and $Marchantia$ (a liverwort) are bryophytes, in which the gametophyte is the main, free-living plant body.
$Adiantum$ is a fern, in which the gametophyte is a small but free-living, photosynthetic prothallus.
Hence the gametophyte is not independent in $Pinus$. -
A prokaryotic autotrophic nitrogen fixing symbiont is found inA prokaryotic, autotrophic nitrogen fixer is a cyanobacterium (blue-green alga) such as $Anabaena$ or $Nostoc$, which is photosynthetic.
$Cycas$ has specialised coralloid roots that are associated with nitrogen-fixing cyanobacteria ($Anabaena\ cycadae$, $Nostoc$).
$Pisum$ (pea) and $Cicer$ (gram) are legumes whose root nodules contain $Rhizobium$, which is prokaryotic but heterotrophic.
$Alnus$ root nodules contain $Frankia$, an actinomycete, which is also heterotrophic.
Hence the prokaryotic autotrophic nitrogen-fixing symbiont is found in $Cycas$.