Questions on Roundworms (Phylum Nematoda)
Roundworms (Phylum Nematoda) – Multiple Choice Questions
1. Roundworms belong to which phylum?
A) Annelida
B) Platyhelminthes
C) Nematoda
D) Arthropoda
E) Mollusca
2. Which of the following best describes the body cavity of roundworms?
A) Acoelomate
B) Pseudocoelomate
C) Coelomate
D) Hemocoel
E) No body cavity
3. Roundworms exhibit which type of body symmetry?
A) Radial
B) Bilateral
C) Asymmetrical
D) Spherical
E) Rotational
4. The digestive system of roundworms is:
A) Absent
B) Incomplete
C) Complete with mouth and anus
D) Extracellular only
E) Shared with excretory
5. The outer body covering of roundworms is called:
A) Cuticle
B) Pellicle
C) Mesoglea
D) Shell
E) Tegument
6. Which of the following is a common disease caused by roundworms in humans?
A) Malaria
B) Ascariasis
C) Tetanus
D) Tuberculosis
E) Ringworm
7. Roundworms are mostly:
A) Flat and segmented
B) Radially symmetrical
C) Cylindrical and unsegmented
D) Worms with parapodia
E) Coelomate with antennae
8. Nematodes eliminate metabolic waste primarily through:
A) Kidneys
B) Malpighian tubules
C) Nephridia
D) Excretory canals and pores
E) Chloragogen cells
9. The nervous system of roundworms consists of:
A) A single nerve net
B) No nervous system
C) Brain only
D) A ring and longitudinal nerve cords
E) Dorsal and ventral roots
10. Roundworm movement is due to:
A) Circular muscles
B) Cilia
C) Longitudinal muscles and hydrostatic pressure
D) Flagella
E) Pseudopodia
11. Which structure is absent in roundworms?
A) Cuticle
B) Mouth
C) Anus
D) Segments
E) Muscles
12. Roundworms reproduce mainly through:
A) Asexual fission
B) Binary fission
C) Hermaphroditism
D) Sexual reproduction with separate sexes
E) Budding
13. Which of the following is a free-living nematode used in scientific research?
A) Ascaris lumbricoides
B) Caenorhabditis elegans
C) Trichinella spiralis
D) Wuchereria bancrofti
E) Enterobius vermicularis
14. Trichinosis is caused by ingestion of:
A) Contaminated water
B) Undercooked pork
C) Mosquito bites
D) Dog saliva
E) Cat feces
15. Which roundworm causes elephantiasis?
A) Hookworm
B) Pinworm
C) Filarial worm
D) Tapeworm
E) Leech
16. What is the function of the cuticle in roundworms?
A) Digestion
B) Sensory input
C) Gas exchange
D) Protection and shape maintenance
E) Circulation
17. What kind of body plan do roundworms exhibit?
A) Radial symmetry with a sac-like body
B) Segmented with true coelom
C) Unsegmented with a pseudocoelom
D) Flat with no cavity
E) Head-foot structure
18. The majority of roundworms are found in:
A) Freshwater only
B) Marine environments only
C) Soil, water, and as parasites
D) Inside plant roots only
E) High altitudes only
19. The disease Enterobiasis (pinworm infection) is common in:
A) Elderly people
B) Children
C) Cats and dogs
D) Fish
E) Birds
20. Which of the following statements is true about roundworms?
A) They have segmented bodies.
B) They lack a digestive system.
C) They have a closed circulatory system.
D) They have separate sexes in most species.
E) They reproduce through binary fission.
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Answers with Explanations
1. C) Nematoda – Roundworms belong to the phylum Nematoda.
2. B) Pseudocoelomate – They have a body cavity not fully lined by mesoderm.
3. B) Bilateral – They have a left and right side that mirror each other.
4. C) Complete with mouth and anus – Their digestive system is a complete tube.
5. A) Cuticle – A protective non-cellular layer secreted by the epidermis.
6. B) Ascariasis – Caused by Ascaris lumbricoides, a parasitic roundworm.
7. C) Cylindrical and unsegmented – Unlike annelids, nematodes are unsegmented.
8. D) Excretory canals and pores – Used to excrete nitrogenous wastes.
9. D) A ring and longitudinal nerve cords – A simple nervous system layout.
10. C) Longitudinal muscles and hydrostatic pressure – Allows thrashing motion.
11. D) Segments – They are unsegmented unlike annelids.
12. D) Sexual reproduction with separate sexes – Most are dioecious.
13. B) Caenorhabditis elegans – A model organism in biology.
14. B) Undercooked pork – May contain Trichinella spiralis cysts.
15. C) Filarial worm – Wuchereria bancrofti causes lymphatic filariasis.
16. D) Protection and shape maintenance – Helps in resisting host digestion and maintaining structure.
17. C) Unsegmented with a pseudocoelom – Their body plan is simple but functional.
18. C) Soil, water, and as parasites – Nematodes inhabit various environments.
19. B) Children – Pinworm infection is common among school-aged children.
20. D) They have separate sexes in most species – Roundworms are mostly dioecious.
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