(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).
© 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.