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2.3 Cnidaria & Ctenophora — Test 1
Q1. The regenerative capacity of Hydra was first discovered by:✓ Trembley
Q2. The 'Portuguese man-of-war' (Physalia) is a:✓ Polymorphic colonial cnidarian
Q3. In Hydra, the nerve cells are arranged as a:✓ Nerve net (multipolar cells)
Q4. Fire coral (a stinging hydrozoan) is represented by:✓ Millepora
Q5. Which is NOT a class of the phylum Cnidaria?✓ Trematoda
Q6. The stinging cells unique to cnidarians, used for defence and capturing prey, are the:✓ Cnidocytes (containing nematocysts)
Q7. The two basic body forms of cnidarians are the:✓ Polyp and medusa
Q8. The free-swimming, ciliated larva of cnidarians is the:✓ Planula
Q9. Cnidarians are diploblastic, with the body wall consisting of an outer ectoderm, an inner endoderm and a middle:✓ Mesoglea (mostly non-cellular jelly)
Q10. The central digestive cavity of a cnidarian, with a single opening, is the:✓ Gastrovascular cavity (coelenteron)
Q11. In Obelia, the medusa typically bears how many tentacles?✓ Sixteen
2.3 Cnidaria & Ctenophora — Test 2
Q12. Sea anemones and corals belong to the cnidarian class:✓ Anthozoa
Q13. True jellyfish, in which the medusa stage dominates, belong to the class:✓ Scyphozoa
Q14. Corals contribute to reef building because their polyps:✓ Secrete a calcium carbonate skeleton
Q15. Reef-building corals depend on symbiotic algae called:✓ Zooxanthellae
Q16. Cnidarians capture prey using nematocysts, which work by:✓ Discharging a coiled thread that pierces or entangles prey
Q17. Polymorphism in a colony like Physalia means that:✓ Different zooids are specialised for different functions
Q18. Comb plates (rows of fused cilia) used for swimming are characteristic of the phylum:✓ Ctenophora
Q19. Ctenophores differ from cnidarians in that ctenophores:✓ Lack true nematocysts and swim using comb plates
Q20. The sting of Physalia and jellyfish is delivered by structures within the cnidocytes called:✓ Nematocysts
Q21. Alternation of generations (metagenesis) in Obelia involves:✓ An asexual polyp stage and a sexual medusa stage
Q22. Hydra moves from place to place mainly by:✓ Looping or somersaulting movements
2.3 Cnidaria & Ctenophora — Test 3
Q23. The cnidarian body shows which kind of symmetry?✓ Radial symmetry
Q24. In cnidarians, digestion is:✓ Partly extracellular in the gastrovascular cavity and partly intracellular
Q25. Sea pens, sea fans and soft corals are all members of the cnidarian class:✓ Anthozoa
Q26. Box jellyfish, known for their potent venom, belong to the class:✓ Cubozoa
Q27. The polyp stage of a cnidarian is typically:✓ Sessile and tubular with an upward mouth and tentacles
Q28. The mesoglea of a jellyfish functions mainly to:✓ Provide bulk and buoyancy (a jelly-like support)
Q29. Cnidarians are considered more advanced than sponges because cnidarians have:✓ True tissues, a nerve net and a mouth
Q30. Colonial corals are ecologically important because they:✓ Build reefs that shelter diverse marine life
Q31. The cnidarian nervous system is described as the most primitive because it:✓ Is a diffuse nerve net with no central control
Q32. A defining adaptation that allowed cnidarians to capture active prey is the:✓ Stinging nematocyst