| 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 |
Which of the following is not a cartilaginous fish?
| 1. Saw fish | 2. Dog fish |
| 3. Sea horse | 4. Sting ray |
| 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 |
| 1. endotherms | 2. marine fishes |
| 3. protochordates | 4. bony fishes |
The structure marked as ‘S’ in the given diagram helps bony fishes in:
| 1. | Oxygenation of blood |
| 2. | Achieving neutral buoyancy |
| 3. | Increasing absorptive surface area for food |
| 4. | Protection of the nerve cord |