Define the following terms:
$(i)$ Prothallus
$(ii)$ Alternation of generation

(N/A) $(i)$ In $Pteridophytes$,spores produced by meiosis germinate to form small,multicellular,free-living,and photosynthetic gametophytes,which are called $Prothallus$.
$(ii)$ In plants,the life cycle involves an alternation between a haploid gametophytic stage (producing gametes) and a diploid sporophytic stage (producing spores). This phenomenon is known as $Alternation$ $of$ $generation$.