Demospongiae MCQs December 4, 2025September 30, 2024 by u930973931_answers 20 min Score: 0 Attempted: 0/20 Subscribe 1. What is the primary characteristic of sponges in the class Demospongiae? (A) They have calcareous spicules. (B) They have siliceous spicules and a fibrous skeleton. (C) They lack spicules. (D) They have organic spicules. 2. Demospongiae sponges are commonly known for their: (A) Spongy texture (B) Glass-like structure (C) Calcium carbonate composition (D) Bright colors 3. Which type of body plan is predominantly found in Demospongiae sponges? (A) Leuconoid (B) Syconoid (C) Asconoid (D) Both A and B 4. What type of spicules do Demospongiae sponges possess? (A) Siliceous spicules, often reinforced with spongin (B) Calcitic spicules (C) Siliceous spicules only (D) Organic spicules only 5. Where are Demospongiae sponges primarily found? (A) Freshwater habitats (B) Marine and freshwater environments (C) Terrestrial environments (D) Intertidal zones only 6. Which of the following is a common characteristic of Demospongiae sponges? (A) They can have both hard and soft bodies. (B) They are exclusively marine. (C) They lack a true cellular organization. (D) They do not filter feed. 7. Demospongiae sponges typically reproduce through which method? (A) Asexual reproduction only (B) Sexual reproduction only (C) Budding only (D) Both asexual and sexual reproduction 8. What is the ecological role of Demospongiae sponges in aquatic environments? (A) Primary producers (B) Filter feeders (C) Predators (D) Decomposers 9. Demospongiae sponges are characterized by their: (A) High metabolic rates (B) Simple body structure (C) Unique canal systems (D) Ability to photosynthesize 10. What type of feeding mechanism do Demospongiae sponges utilize? (A) Absorption (B) Predation (C) Photosynthesis (D) Filter feeding 11. Which of the following best describes the physical structure of Demospongiae sponges? (A) Gelatinous and soft (B) Rigid and hard (C) Hard and calcareous (D) Flexible and leathery 12. Demospongiae sponges can be found at what depths in the ocean? (A) Less than 10 meters (B) They can be found at all depths, including deep-sea habitats. (C) 100 to 1000 meters (D) 10 to 100 meters 13. Which of the following is NOT a characteristic of Demospongiae sponges? (A) Siliceous spicules (B) Presence of oscula (C) Complex canal systems (D) Ability to photosynthesize 14. What larval stage do Demospongiae sponges undergo? (A) Parenchymella (B) Planula (C) Trochophore (D) Veliger 15. Which of the following is a genus of sponges in the class Demospongiae? (A) Spongilla (B) Clathrina (C) Euplectella (D) Oscillatoria 16. What is the primary mode of locomotion for Demospongiae sponges? (A) Swimming (B) Crawling (C) They are sessile (non-moving). (D) Burrowing 17. Which type of skeleton do Demospongiae sponges have? (A) Calcareous skeleton (B) No skeleton (C) Organic skeleton (D) Siliceous skeleton 18. Demospongiae sponges are known for their: (A) Long lifespan (B) Rapid growth (C) Bright coloration (D) Ability to regenerate quickly 19. What is the role of the mesohyl in Demospongiae sponges? (A) Nutrient transport and structural support (B) Water circulation (C) Gas exchange (D) All of the above 20. Which ecological role do Demospongiae sponges fulfill? (A) Primary consumers (B) Secondary producers (C) Filter feeders and habitat providers (D) Decomposers