1. | They have bilateral symmetry as adults and radial symmetry as larvae. |
2. | They are triploblastic and coelomates. |
3. | They possess a well-developed excretory system. |
4. | They have an incomplete digestive system. |
Statement 1: | Hemichordates were earlier considered as a sub-phylum under Phylum Chordata but are now placed separately in a phylum under non-Chordata. |
Statement 2: | Hemichordates have a rudimentary structure in the collar region called stomochord, a structure homologous to the notochord. |
1. | Both Statement 1 and Statement 2 are correct but Statement 2 does not explain Statement 1. |
2. | Statement 1 is correct and Statement 2 is incorrect. |
3. | Both Statement 1 and Statement 2 are incorrect. |
4. | Both Statement 1 and Statement 2 are correct and Statement 2 explains Statement 1. |
1. | Circulatory system is a closed type |
2. | Proboscis gland is a digestive gland that secretes a large number of hydrolytic enzymes |
3. | Respiration takes place through the gills |
4. | Sexes are not separate, fertilization is internal and development is direct |
a. | A notochord |
b. | Ventral, solid, and double central nervous system |
c. | Pharynx perforated by gill slits |
d. | Ventral heart |
e. | Terminal anus and a lack of post-anal tail |
1. | a, c, and d only | 2. | a, b. and e only |
3. | a and c only | 4. | b, c, and d only |
Statement I: | In Urochordata, notochord is present only in larval tail. |
Statement II: | In Cephalochordata, notochord extends from head to tail region and is persistent throughout their life. |
Statement III: | Both Urochordates and Cephalochordates are exclusively marine. |
Statement I: | All vertebrates are chordates but all chordates are not vertebrates. |
Statement II: | Besides the basic chordate features, all vertebrates have at least a three-chambered heart and paired appendages. |
1. | Both Statement I and Statement II are correct but Statement II does not explain Statement I. |
2. | Statement I is correct and Statement II is incorrect. |
3. | Both Statement I and Statement II are incorrect. |
4. | Both Statement I and Statement II are correct and Statement II explains Statement I. |
1. | 3 | 2. | 4 |
3. | 5 | 4. | 6 |
I: | They are marine but migrate for spawning to fresh water. |
II: | After spawning, within a few days, they die. |
III: | Their larvae, after metamorphosis, return to the ocean. |
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 |
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] |