Explain how the fern sporophyte is dependent upon the gametophyte

All plant types switch off by generations. The trend which is happening recently is that the sporohyte is dependent upon autotrophic gametophytes to the oppositeâ€gametophytes which are dependent on autotrophic sporophytes. This trend is more visible by viewing the life cycles of the of a moss, a fern, and an angiosperm.