1. | They are mostly aquatic animals and their body is covered by dry and cornified skin, dermal scales or scutes. |
2. | They do not have external ear openings. Tympanum represents ear. |
3. | Heart is usually three-chambered, but four-chambered in crocodiles. |
4. | They are oviparous and development is direct. |
I: | The digestive tract of birds has additional chambers, the crop and gizzard. |
II: | Air sacs connected to lungs supplement respiration. |
III: | They possess beak with teeth. |
1. | Only I and II are correct | 2. | Only I and III are correct |
3. | Only II and III are correct | 4. | I, II and III are correct |
1. | Mouth is ventral, teeth are modified ctenoid scales and directed forwards. |
2. | Mouth is ventral, teeth are modified placoid scales and directed backwards. |
3. | Mouth is dorsal, teeth are modified ctenoid scales and directed forwards. |
4. | Mouth is dorsal, teeth are modified placoid scales and directed backwards. |
Statement I: | Protochordates are exclusively marine. |
Statement II: | In Urochordata, notochord is present only in larval tail, while in Cephalochordata, it extends from head to tail region and is persistent throughout their life. |
I: | the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. |
II: | bilateral symmetry, triploblastic body organisation, true coelom with organ-system level of organisation. |
III: | a post anal tail and a closed circulatory system. |
Assertion (A): | Hemichordata was earlier considered as a sub-phylum under phylum Chordata but now it is placed as a separate phylum under non-chordata. |
Reason (R): | Hemichordates have a rudimentary structure in the collar region called stomochord, a structure analogous to notochord. |
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. |
I: | They are bilaterally symmetrical, triploblastic and coelomate animals. |
II: | Body is covered by a calcareous shell and is segmented with a distinct head, muscular foot and visceral hump as metameres. |
III: | A soft and spongy layer of skin forms a mantle over the visceral hump. |
IV: | They are usually dioecious and oviparous with indirect development. |
1. | Annelids | 2. | Mollusca |
3. | Round worms | 4. | Arthropods |