question_answer 17)

  A prothallus is (a) a structure in Pteridophyta formed before the thallus develops (b)asporophytic free living structure formed in Pteridophyta (c) a gametophyte free living structure formed in Pteridophyta (d) a primitive structure formed after fertilization in Pteridophyta

Answer:

                  (c) Prothallus is usually a gametophytic stage in the life of a Pteridophyta . Spore germinates to form a prothalium, it is short lived inconspicuous heart shaped structure with a number of rhizoids developed beneath and sex organs, archegonium and antheridium.