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. |
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. | 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. | Most have two pairs of limbs and tail is present in some. |
2. | Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca which opens to the exterior. |
3. | Respiration is by gills, lungs and through skin. |
4. | The heart is two chambered with one atrium and one ventricle. |
I: | Body is covered by dry and cornified skin, dermal scales or scutes. |
II: | External ear is not present and tympanum represents the ear. |
III: | Scales are shed as skin cast in all members. |
IV: | Fertilization is internal and development is direct. |
1. | Only II is correct | 2. | Only II and IV are correct |
3. | All are correct | 4. | Only I and II are incorrect |
1. | Crocodile | 2. | Wall lizard |
3. | Turtle | 4. | Tortoise |