1. | Choanocyte and helps sponges in movement of water through their canal system |
2. | Choanocyte and helps sponges in reproducing asexually under favourable conditions |
3. | Cnidocyte and helps sponges in catching their prey by paralyzing them |
4. | Colloblast and helps sponges in sticking to a surface |
1. | Water enters the sponge body through ostia into a spongocoel from where it goes out through the osculum. |
2. | Body is supported by a skeleton made up of spicules or spongin fibres. |
3. | Sexes are not separate. |
4. | Fertilization is external. |
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Regarding the cell shown in the given figure:
I: The name Cnidaria is derived from this cell | |
II: The stinging capsule present in the cell is called as nematode | |
III: These cells help cnidarians in anchorage, defence and in capturing the prey |
1. While I and II are correct, III is incorrect
2. I, II and III are correct
3. Only II is incorrect
4. Only I is correct
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1. | Gastrovascular cavity has a single opening, mouth on hypostome. |
2. | Corals are cnidarians and have a skeleton of calcium carbonate. |
3. | They exhibit tissue level of organization and are diploblastic. |
4. | Digestion is exclusively intracellular. |
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I: | Polyp is sessile and cylindrical form as seen in Hydra and Adamsia. |
II: | Medusa is umbrella-shaped and free swimming form as seen in Aurelia. |
1. | Only I is correct | 2. | Only II is correct |
3. | Both I and II are correct | 4. | Both I and II are incorrect |
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a: | both polyp and medusa forms exist during its life cycle |
b: | metagenesis, a sort of alternation of generation, is seen |
c: | polyps produce medusae sexually and medusae form the polyps sexually |
1. | only a is correct | 2. | only a and b are correct |
3. | only c is correct | 4. | a, b and c are correct |
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Column I | Column II | ||
A. | Physalia | P. | Sea-fan |
B. | Adamsia | Q. | Sea anemone |
C. | Pennatula | R. | Sea-pen |
D. | Gorgonia | S. | Portuguese men of war |
A | B | C | D | |
1. | S | Q | R | P |
2. | S | R | Q | P |
3. | P | Q | R | S |
4. | S | P | Q | R |
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a: | body bears eight external rows of ciliated comb plates, which help in locomotion. |
b: | reproduction takes place only by asexual means. |
c: | digestion is both extracellular and intracellular. |
d: | sexes are separate. |
1. | a and c only | 2. | b and d only |
3. | a, b and c only | 4. | a, b and d only |
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Statement I: | Planaria is a free-living flatworm and possesses high regeneration capacity. |
Statement II: | Hooks and suckers are present in parasitic flatworms. |
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The structure shown in the given figure helps flatworms in:
1. Catching food and digesting it
2. Exchange of gases
3. Excretion and Osmoregulation
4. Regeneration of lost body parts
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