Chondrichthyes is characterised by
Placoid scale
Ventral mouth
Ctenoid scale and ventral mouth
Placoid scale and ventral mouth
D.
Placoid scale and ventral mouth
Chondrichthyes is one of the classes of super-class-Pisces, sub-phylum-Vertebrata and phylum Chordata. The members of class-Chondrichthyes are marine animals with a streamlined body and have a cartilaginous endoskeleton. Mouth is located ventrally. The skin is tough, containing minute placoid scales. The teeth are modified placoid scales which are backwardly directed, e.g., Dog fish (Scoliodon), sawfish (Pristis), great white shark (Carcharodorus sting ray (Trygon), etc.
Consider the following statements and Choose correct ones from given options.
(I) Shark do not have any bone in its body.
(II) Water snake and salamander belongs to same class and have largest RBC.
(III) Silver fish is a true fish while cuttle and star fishes are mollusks and echinoderms respectively.
(IV) Ornithorhynchus is a connecting link between reptiles and mammals.
I, II and IV
I and IV
I, II and III
III and IV
A horse and a donkey can breed to produce mule which is an infertile animal. The infertility is because horse and donkey belong to different.
Class
Order
Species
Genus
The structure present in all adult vertebrates is
Notochord
Dorsal tubular nerve cord
Pharyngeal gill slits
All of these
Animals of class-Mammalia have
Seven cervical vertebrae
Seven cranial nerve
Single ventricular chamber
Fourteen cervical vertebrae
Match the following Columns.
| Column I (organism) | Column II (Connecting Link) |
| A. Echina | 1. Between Annelida and Mollusca |
| B. Peripatus | 2. Between Reptiles and Mammals |
| C. Neopilina | 3. Between Annelida and Arthropoda |
| D. Protopterus | 4. Between Pisces and Amphibian |
A – 4; B – 3; C – 2; D – 1
A – 2; B – 3; C – 1; D – 4
A – 3; B – 1; C – 2; D – 4
A – 4; B – 2; C – 1; D – 3
