Heterospory and Plant Evolution — NEET Biology

Correct answer: B — S1, S3, S4 and S5 only

Let's evaluate each statement based on NCERT text: S1: Correct. The NCERT states, 'Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous.' S2: Incorrect. The NCERT clearly states, 'The megaspores and microspores germinate and give rise to female and male gametophytes, respectively.' This statement reverses the roles of megaspores and microspores. S3: Correct. The NCERT mentions, 'The female gametophytes in these plants are retained on the parent sporophytes for variable periods... This event is a precursor to the seed habit.' S4: Correct. The NCERT lists 'Selaginella' as an example of a heterosporous pteridophyte that shows this precursor event. S5: Correct. The NCERT states, 'The development of the zygotes into young embryos take place within the female gametophytes. This event is a precursor to the seed habit.' S6: Incorrect. The NCERT states, 'In majority of the pteridophytes all the spores are of similar kinds; such plants are called homosporous.' Also, pteridophytes are not seed-producing plants but show a precursor to the seed habit. Therefore, statements S1, S3, S4, and S5 are correct. The final answer is B.