Coelenterates are aquatic mostly marine except Hydra and they mostly found in colonies and some are solitary. They have a tissue-level organization. They have a mouth but no head or brain. They are acoelomates and they exhibit blind sac body plans. They have an incomplete digestive system and they respire through the body surface. They show radial symmetry except for Meridium, which shows biradial symmetry. Nematoblast or Cnidoblast cells are the characteristic cells of this phylum. Nematoblast cells are formed by intestinal cells and later on when fully developed migrate to tentacles. They are stimulated mechanically and chemically. Once discharges they cannot be used again so they are merged back to the gastrovascular cavity where they are replaced by fresh nematoblast after every 48 hours. These cells are absent on the basal disc and they inject poison to paralyze the prey. So, take this quiz and know more about the phylum Coelenterata.
1. Which of the following inhabit freshwater bodies?
A. Hydrozoans
B. Anthozoans
C. Ctenophores
D. Scyphozoans
2. Cnidarians are ...
A. Only fresh water
B. Only marine
C. Aquatic
D. Terrestrial
3. Portuguese man of war is ....
A. Aurelia
B. Physalia
C. Pluerobranchia
D. Obelia
4. Which part of the Hydra lacks nematoblasts?
A. Pedal disc
B. Stomach region
C. Manubrium
D. Tentacles
5. Aurelia generally known as ...
A. Jelly fish
B. Marine fish
C. Jolly fish
D. True fish
6. Hydra receives stimuli through....
A. Nerve cells
B. Nerve net
C. Nematocytes
D. Sensory cells
7. Which of the following has nerve cells but no brain?
A. Protozoan
B. Hydra
C. Sponge
D. Cockroach
8. The gas gland is present in ...
A. Gorgonia
B. Penatula
C. Physalia
D. Red coral
9. Hypnotoxin is ...
A. Protein
B. Lipid
C. Carbohydrate
D. Glycolipid
10. In Cnidaria, the balancing structures in medusa are ....
A. Otoliths
B. Statocysts
C. Statoliths
D. None of these
11. Excretion of nitrogenous waste in Hydra takes place through....
A. Nephridia
B. Flame cell
C. Anus
D. General body surface
12. In which of the following complete absence of medusa stage is found?
A. Obelia
B. Aurelia
C. Metridium
D. All of the above
13. Which one is bioluminescent?
A. Aurelia
B. Adamsia
C. Astraea
D. Metridium
14. Which of the following is a coral island?
A. Iceland
B. Srilanka
C. Lakshadweep
D. Mumbai
15. Cnidoblast is present in ....
A. Epidermis
B. Gadtrodermis
C. Both of these
D. None of these
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