UPSC Prelims 2001 Q132: Science & Technology – Biology
Consider the following statements:
I. Tapeworm is a hermaphrodite.
II. Round - worm has separate sexes.
III. Filaria is caused by a nematode.
IV. Guinea worm is an annelid.
Which of these are correct?
- (a) I and II
- (b) I, II and III
- (c) III and IV
- (d) II, III and IV
Answer: (b) I, II and III
Explanation
Statements about worms
| Statement | Verdict |
|---|---|
| I. Tapeworm is a hermaphrodite | Correct — each segment has male and female organs (flatworm) |
| II. Roundworm has separate sexes | Correct — Ascaris is dioecious |
| III. Filaria is caused by a nematode | Correct — Wuchereria bancrofti, spread by Culex mosquitoes |
| IV. Guinea worm is an annelid | Wrong — Dracunculus is a nematode (roundworm) |
Statements I, II and III are correct. The guinea worm is a nematode, not an annelid; annelids are segmented worms such as earthworms and leeches. India was certified free of guinea worm disease in 2000.
Answer: (b) I, II and III.
Why each option is right or wrong
- (a) Incorrect. Statement III on filaria is also correct.
- (b) CORRECT. I, II and III are right; the guinea worm is a nematode.
- (c) Incorrect. Statement IV is wrong, and I and II are left out.
- (d) Incorrect. Statement IV is wrong.
Key point
Phyla: Platyhelminthes (tapeworm, liver fluke), Nematoda (Ascaris, filaria, guinea worm), Annelida (earthworm, leech).
Remember
Guinea worm and filaria are nematodes; tapeworm is a hermaphrodite flatworm.
Common mistakes
- Calling the guinea worm an annelid because of 'worm'.
- Thinking roundworms are hermaphrodites.
- Forgetting filaria is caused by a nematode.
Exam tip
Segmented = annelid; unsegmented round = nematode; flat = platyhelminth.
Sources
- NCERT Class XI — Biology, chapter 'Animal Kingdom'
- World Health Organization — Dracunculiasis (guinea-worm disease) fact sheet