According to the textbook, the life cycle of pteridophytes proceeds as follows:

1. The sporophyte bears sporangia where meiosis in spore mother cells (B) produces spores .
2. These spores germinate to give rise to a multicellular, free-living gametophyte called the prothallus (A) .
3. The gametophyte (prothallus) bears the sex organs, which involves the formation of archegonia and antheridia (D) .
4. Male gametes released from antheridia fuse with the egg in the archegonium, a process called fertilisation (C), to form a zygote .