| 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 |
| I: | Four pairs of gills covered by an operculum on each side |
| II: | Skin covered with placoid scales |
| III: | Regulation of buoyancy by an air bladder |
| Assertion (A): | The swim bladder is an essential organ for bony fishes. |
| Reason (R): | It allows them to maintain buoyancy without expending energy. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
| 1. | Heart is two chambered |
| 2. | Cold blooded animals |
| 3. | Sexes separate but fertilization is usually internal |
| 4. | Mostly oviparous |
| 1. | marine bony fish |
| 2. | fresh water bony fish |
| 3. | cartilaginous fish |
| 4. | limbless amphibian |
| 1. Angel fish | 2. Flying fish |
| 3. Star fish | 4. Fighting fish |
| 1. endotherms | 2. marine fishes |
| 3. protochordates | 4. bony fishes |