Given below are the stages in the life cycle of pteridophytes. Arrange the following stages in the correct sequence. A. Prothallus stage B. Meiosis in spore mother cells C. Fertilisation D. Formation of archegonia and antheridia in gametophyte. E. Transfer of antherozoids to the archegonia in presence of water. Choose the correct answer from the options given below:

Solution & Explanation

Answer: (C) B, A, D, E, C. Solution: In the pteridophyte life cycle the diploid sporophyte's sporangia produce spores by meiosis in spore mother cells (B); the spores germinate into the prothallus/gametophyte (A); the prothallus then bears the sex organs archegonia and antheridia (D); water transfers the antherozoids from antheridia to the archegonia (E); and finally fusion of male gamete with the egg gives fertilisation and the zygote (C). This gives the order B, A, D, E, C, so option C is correct. NCERT Reference: Class XI Biology, Plant Kingdom, p.30, line 43 — "The sporangia produce spores by meiosis in spore mother cells"; and p.32, lines 8-11 — "The gametophytes bear male and female sex organs called antheridia and archegonia... Water is required for transfer of antherozoids... Fusion of male gamete with the egg present in the archegonium result in the formation of zygote."