Question: 111. 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:
(1) \mathrm{B}, \mathrm{A}, \mathrm{D}, \mathrm{E}, \mathrm{C}
(2) \mathrm{B}, \mathrm{A}, \mathrm{E}, \mathrm{C}, \mathrm{D}
(3) \mathrm{D}, \mathrm{E}, \mathrm{C}, \mathrm{A}, \mathrm{B}
(4) \mathrm{E}, \mathrm{D}, \mathrm{C}, \mathrm{B}, \mathrm{A}
Answer: Option (1)
Explanation:
In pteridophytes, the dominant plant body is the sporophyte.
Spore mother cells in sporangia undergo meiosis to produce haploid spores, which is the first step.
These spores germinate to form a haploid gametophyte called the prothallus.
The prothallus develops male sex organs (antheridia) and female sex organs (archegonia).
In the presence of water, motile antherozoids are transferred from antheridia to archegonia.
Fusion of male and female gametes then occurs, resulting in fertilisation.
Thus, the correct sequence is B → A → D → E → C.