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. |
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. |
A | B | C | D | |
1. | Phylum | Cephalochordata | Urochordata | Protochordata |
2. | Division | Agnatha | Super-Class | Pisces |
3. | Phylum | Protochordata | Infra-class | Jawless fishes |
4. | Division | Agnatha | Sub-division | Pisces |
1. | 3 | 2. | 4 |
3. | 5 | 4. | 6 |
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. |
1. | Petromyzon, Myxine |
2. | Ascidia, Salpa |
3. | Pristis, Doliolum |
4. | Branchiostoma, Balanoglossus |
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 |
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] |
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 |
1. Angel fish | 2. Flying fish |
3. Star fish | 4. Fighting fish |