| Assertion (A): | Echinoderms possess an endoskeleton of calcareous ossicles. |
| Reason (R): | These organisms are marine or freshwater dwellings. |
| 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. | Both (A) and (R) are false. |
| Assertion (A): | Balanoglossus possess external fertilization. |
| Reason(R): | Saccoglossus undergo direct development during their life cycle. |
| 1. | Both (A) and (R) are True and (R) correctly explains (A) |
| 2. | Both (A) and (R) are True and (R) does not correctly explain (A) |
| 3. | (A) is True, (R) is False |
| 4. | (A) is False, (R) is False |
| Assertion (A): | Aschelminths and Annelids possess bilateral symmetry. |
| Reason (R): | Both Aschelminths and Annelids are coelomates |
| 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. | Both (A) and (R) are false. |
| Assertion (A): | Choanocytes or collar cells line the spongocoel and the canals in poriferans. |
| Reason (R): | Poriferans possess spicules and spongin fibres. |
| 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. | Both (A) and (R) are False. |
| Assertion (A): | All vertebrates are chordates but all the chordates are not vertebrates. |
| Reason (R): | All the vertebrates are characterised by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits at some stages of the life cycle. |
| 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. | Both (A) and (R) are false. |
| 1. | Metamerism first developed in Arthropoda |
| 2. | Triploblastic animals lacking coelom are platyhelminths and annelids |
| 3. | Coelomate animals in which blastopore forms anus are grouped under deuterostomes |
| 4. | Coelom is the body cavity found between ectoderm and outer body wall |
| 1. | Archaeopteryx is thought to be the transitional fossil between dinosaurs and birds since, like birds Archaeopteryx had feathers and a fused collar-bone indicating the flying ability |
| 2. | Cloaca is present in Balenoptera |
| 3. | In Physalia, digestion is first extracellular and then intracellular digestion occurs |
| 4. | Both (1) and (3) |
| 1. | Branchostoma : Notochord persist through out the life |
| 2. | Ascidia : Notochord present in larva and disappears in adult |
| 3. | Doliolum : Notochord present in the larval tail only |
| 4. | More than one option is correct |
| 1. | May or may not possess jaw |
| 2. | Is included in the division Agnatha where notochord is present only in the early stages |
| 3. | Possess an elongated body with gill slits for respiration |
| 4. | Are devoid of scales and possess paired fins |