Q5. Match each plant with its group: Selaginella, Sphagnum, Chlamydomonas (from NCERT Exercise Q10(c)).
Selaginella is a pteridophyte, Sphagnum a moss (bryophyte) and Chlamydomonas an alga (NCERT pages 26, 30 and 32).
Q6. Selaginella and Lycopodium are both in Lycopsida. Are both heterosporous?
No. NCERT names only Selaginella and Salvinia as heterosporous (page 32); beyond the NCERT text, Lycopodium is homosporous.
Q7. Do pteridophytes bear seeds?
No; they reproduce by spores. The embryo in a retained female gametophyte is only a precursor to the seed habit; seeds appear in gymnosperms (NCERT page 32).
Q8. Which is the dominant phase in the life cycle of a pteridophyte, and how does it differ from a bryophyte?
The sporophyte is dominant in pteridophytes; in bryophytes the dominant phase is the gametophyte (NCERT pages 30 and 32).
Q9. What are the male gametes of pteridophytes called, and what do they need to reach the archegonium?
Antherozoids; they need water to be carried to the mouth of the archegonium (NCERT page 32).
Q10. Assertion: pteridophytes are found mostly in cool, damp, shady places. Reason: their gametophytes require cool, damp, shady places, and fertilisation needs water. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion: these needs restrict living pteridophytes to narrow geographical regions (NCERT pages 30 and 32).
Q11. Is every pteridophyte gametophyte free-living?
No. The prothallus of homosporous pteridophytes is free-living, but in Selaginella and Salvinia the female gametophyte is retained on the parent sporophyte for variable periods. In gymnosperms neither gametophyte is ever free-living (page 33).
Q12. Which phases of a fern are independent?
Both: the free-living prothallus and the dominant sporophyte (NCERT pages 30 and 32); in bryophytes the sporophyte depends on the gametophyte (page 29).