A: | Presence of a mid-dorsal, solid and double nerve cord. |
B: | Presence of closed circulatory system. |
C: | Presence of paired pharyngeal gill slits |
D: | Presence of dorsal heart. |
E: | Triploblastic pseudocoelomate animals. |
1. | C, D and E only | 2. | A, C and D only |
3. | B and C only | 4. | B, D and E only |
Assertion (A): | All vertebrates are chordates but all chordates are not vertebrates. |
Reason (R): | Notochord is replaced by vertebral column in the adult vertebrates. |
1. | (A) is false, (R) is true. |
2. | Both (A) and (R) are true and (R) correctly explains (A). |
3. | Both (A) and (R) are true and (R) does not correctly explain (A). |
4. | (A) is true, (R) is false. |
Which one of the following features are not true for chordates?
(a) Heart is dorsal.
(b) Pharynx is perforated by gill slits.
(c) Central nervous system is ventral, solid and single.
(d) Post-anal tail is present.
(e) Notochord is present.
Choose the most appropriate answer from the option give below:
1. | (e) only | 2. | (a), (d) and (c) only |
3. | (b) and (c) only | 4. | (a) and (c) only |
All vertebrates are chordates but all chordates are not vertebrates, why?
1. | Notochord is replaced by a vertebral column in the adults of some chordates. |
2. | The ventral hollow nerve cord remains throughout life in some chordates. |
3. | All chordates possess a vertebral column. |
4. | All chordates possess notochords throughout their lives. |
Consider the following features:
A: Organ system level of organisation
B: Bilateral symmetry
C: True coelom with segmentation of body
Select the correct option of animal groups that possess all the above characteristics:
1. | Annelida, Mollusca and Chordata |
2. | Annelida, Arthropoda and Chordata |
3. | Annelida, Arthropoda and Mollusca |
4. | Arthropoda, Mollusca and Chordata |
An important characteristic that Hemichordates share with Chordates is:
1. Ventral tubular nerve cord
2. Pharynx with gill slits
3. Pharynx without gill slits
4. Absence of notochord
Choose the correct statement.
1. All mammals are viviparous
2. All cyclostomes do not possess jaws and paired fins
3. All reptiles have a three-chambered heart
4. All Pisces have gills covered by an operculum