Holothuroidea MCQs January 8, 2026September 28, 2024 by u930973931_answers 30 min Score: 0 Attempted: 0/30 Subscribe 1. What is the common name for members of the class Holothuroidea? (A) Sea stars (B) Sea urchins (C) Sand dollars (D) Sea cucumbers 2. Which feature distinguishes Holothuroidea from other echinoderms? (A) Hard, calcareous endoskeleton (B) Presence of spines (C) Soft-bodied with a leathery skin (D) Radial symmetry 3. What is the primary mode of feeding for most Holothuroidea? (A) Filter feeding (B) Predation (C) Detritivorous feeding (D) Herbivorous feeding 4. Which structure do Holothuroidea use for locomotion? (A) Spines (B) Tentacles (C) Tube feet (D) Flagella 5. How do Holothuroidea respire? (A) Through gills (B) They do not respire (C) Through specialized lungs (D) Through their skin and cloaca 6. Which of the following is a defense mechanism used by Holothuroidea? (A) Ejecting toxins (B) Camouflage (C) Hard shells (D) Evisceration 7. What role do Holothuroidea play in marine ecosystems? (A) They help recycle nutrients and aerate the substrate. (B) They are primary producers. (C) They serve as keystone species. (D) They compete with fish for food. 8. Which of the following is NOT a characteristic of Holothuroidea? (A) Spiny skin (B) Tube feet (C) Soft body (D) Radial symmetry 9. How do Holothuroidea reproduce? (A) External fertilization (B) Internal fertilization (C) Asexual budding (D) Parthenogenesis 10. What is the primary habitat of Holothuroidea? (A) Marine environments (B) Terrestrial (C) Freshwater (D) Estuaries 11. Which structure in Holothuroidea is used for feeding and sensing the environment? (A) Tentacles (B) Tube feet (C) Cloaca (D) Madreporite 12. What is the function of the cloaca in Holothuroidea? (A) It functions in excretion and reproduction. (B) It serves as a respiratory organ. (C) It aids in locomotion. (D) It is used for digestion. 13. Which of the following describes the body shape of Holothuroidea? (A) Flat and disk-like (B) Irregular and asymmetrical (C) Star-shaped (D) Cylindrical and elongated 14. What type of feeding behavior is observed in Holothuroidea? (A) Suspension feeding (B) Grazing (C) Detritivory (D) Carnivorous feeding 15. Which part of the Holothuroidea’s anatomy helps it to capture food particles? (A) Spines (B) Tube feet (C) Tentacles (D) Madreporite 16. What is the primary purpose of the calcareous ring in Holothuroidea? (A) Defense against predators (B) Respiration (C) Structural support for the body wall (D) Feeding 17. How do Holothuroidea contribute to sediment turnover in their habitats? (A) By competing with fish (B) By predating on burrowing organisms (C) By feeding on algae (D) By burrowing into the substrate 18. Which feature allows Holothuroidea to adapt to different substrates? (A) Evisceration (B) Ability to regenerate lost parts (C) Presence of spines (D) Soft and flexible body 19. What is the role of the respiratory trees in Holothuroidea? (A) Digestion (B) Circulation (C) Respiration (D) Excretion 20. Which of the following describes the locomotion of Holothuroidea? (A) Rapid swimming (B) Gliding (C) Floating (D) Crawling on the ocean floor 21. Which of the following is a major threat to Holothuroidea populations? (A) All of the above (B) Habitat destruction (C) Pollution (D) Overfishing 22. What characteristic allows Holothuroidea to defend themselves from predators? (A) Evisceration (B) Ejecting toxins (C) Hard shells (D) Speed 23. What type of symmetry do Holothuroidea exhibit? (A) Radial symmetry (B) Pentaradial symmetry (C) Bilateral symmetry (D) Asymmetry 24. Which of the following is an example of a commercially important Holothuroidea? (A) Sea star (B) Sea urchin (C) Sand dollar (D) Sea cucumber 25. What do Holothuroidea primarily feed on in their natural habitats? (A) Plankton (B) Algae (C) Detritus and organic matter (D) Other echinoderms 26. Which adaptation helps Holothuroidea survive in environments with high sedimentation? (A) Ability to swim (B) Ability to camouflage (C) Hard outer shell (D) Soft body that can burrow 27. How do Holothuroidea help maintain healthy marine ecosystems? (A) By consuming large amounts of fish (B) By filtering water (C) By competing with other echinoderms (D) By recycling nutrients in the sediment 28. What happens to the internal organs of Holothuroidea during evisceration? (A) They regenerate immediately (B) They become hardened (C) They are expelled and can be regenerated later (D) They are permanently lost 29. What is the significance of the leathery body wall in Holothuroidea? (A) It protects against physical damage. (B) It provides buoyancy. (C) It aids in locomotion. (D) It helps with digestion. 30. What do Holothuroidea and other echinoderms share in common? (A) Presence of a dorsal nerve cord (B) Hard exoskeleton (C) Segmented body plan (D) Water vascular system