Q. No.Consider the given two statements:
Statement 1:
Hemichordates were earlier considered as a sub-phylum under Phylum Chordata but are now placed separately in a phylum under non-Chordata.
Statement 2:
Hemichordates have a rudimentary structure in the collar region called stomochord, a structure homologous to the notochord.
1.
Both Statement 1 and Statement 2 are correct but Statement 2 does not explain Statement 1.
2.
Statement 1 is correct and Statement 2 is incorrect.
3.
Both Statement 1 and Statement 2 are incorrect.
4.
Both Statement 1 and Statement 2 are correct and Statement 2 explains Statement 1.
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| 1. | Circulatory system is a closed type |
| 2. | Proboscis gland is a digestive gland that secretes a large number of hydrolytic enzymes |
| 3. | Respiration takes place through the gills |
| 4. | Sexes are not separate, fertilization is internal and development is direct |
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| a. | A notochord |
| b. | Ventral, solid, and double central nervous system |
| c. | Pharynx perforated by gill slits |
| d. | Ventral heart |
| e. | Terminal anus and a lack of post-anal tail |
| 1. | a, c, and d only | 2. | a, b. and e only |
| 3. | a and c only | 4. | b, c, and d only |
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| Statement I: | In Urochordata, notochord is present only in larval tail. |
| Statement II: | In Cephalochordata, notochord extends from head to tail region and is persistent throughout their life. |
| Statement III: | Both Urochordates and Cephalochordates are exclusively marine. |
1. Only Statement I and Statement II
2. Only Statement I and Statement III
3. Only Statement II and Statement III
4. Statement I, Statement II, and Statement III
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| Statement I: | All vertebrates are chordates but all chordates are not vertebrates. |
| Statement II: | Besides the basic chordate features, all vertebrates have at least a three-chambered heart and paired appendages. |
| 1. | Both Statement I and Statement II are correct but Statement II does not explain Statement I. |
| 2. | Statement I is correct and Statement II is incorrect. |
| 3. | Both Statement I and Statement II are incorrect. |
| 4. | Both Statement I and Statement II are correct and Statement II explains Statement I. |
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a. All living members are ectoparasites on some fishes.
b. The body bears 6-15 pairs of gill slits for respiration.
c. They have a sucking and circular mouth without jaws.
d. Their body is devoid of scales and paired fins.
e. Cranium and vertebral column are bony.
f. Circulation is of open type.
| 1. | 3 | 2. | 4 |
| 3. | 5 | 4. | 6 |
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| I: | They are marine but migrate for spawning to fresh water. |
| II: | After spawning, within a few days, they die. |
| III: | Their larvae, after metamorphosis, return to the ocean. |
2. Only I and II are correct
3. Only II and III are correct
4. I, II and III are correct
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| 1. | are marine animals and have cartilaginous endoskeleton |
| 2. | have a mouth located dorsally |
| 3. | have teeth that are modified cycloid or ctenoid scales directed backwardly |
| 4. | have the capacity to regulate their body temperature |
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| 1. | In males, pelvic fins bear claspers |
| 2. | Some of them have electric organs [Torpedo] |
| 3. | None of them is viviparous |
| 4. | Some possess poison sting [Trygon] |
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| I: | They have four pairs of gills which are covered by an operculum on each side. |
| II: | Due to the absence of air bladder, they have to swim constantly to avoid sinking. |
| III: | Skin is covered with placoid scales. |
| IV: | Mouth is mostly terminal. |
| 1. | Only II | 2. | Only II and III |
| 3. | Only I and IV | 4. | Only IV |
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