(a) The life cycle has two phases - sporophytic and gametophytic which are diploid (2n) and haploid (n) respectively.
(b) The sporophyte undergoes meiosis to form haploid spores (n).
(c) These spores germinate into gametes (gametophyte).
(d) The male and female gametes fuse to form diploid (2n) zygote, which gives rise to sporophyte. This phenomenon is called alternation of generation.