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 |
i. | Snakes lack urinary bladder |
ii. | Air sacs in birds are helpful to lessen the body weight, keep the body warm, regulate body temperature and help in blood circulation |
iii. | Bone marrow is abundantly present in birds |
iv. | Devil fish belongs to the phylum Mollusca |
v. | Sea urchin has mouth on lower side and anus on the upper side |
Animals | Morphological features | |
(a) | Scorpion, spider, cockroach | Ventral solid nerve cord |
(b) | Centipede, prawn, sea-urchin | Joined appendages |
(c) | Cockroach, Locust, Taenia | Metameric segmentation |
(d) | Liver fluke, sea-anemone, sea-cucmber | Bilateral symmetry |