Which one of the following groups of animals is correctly matched with its characteristic feature without any exception?
- Reptilia : possess 3-chambered heart with an incompletely divided ventricle
- Chordata : possess a mouth with an upper and a lower jaw
- Chondrichthyes : possess cartilaginous endoskeleton
- Mammalia : give birth to young ones
Answer
(3) Chondrichthyes : possess cartilaginous endoskeleton
Solution
∵ Crocodiles have a 4-chambered heart ⇒ (1) has an exception.
∵ Cyclostomes (e.g. Petromyzon) are jawless chordates ⇒ (2) has an exception.
∵ Egg-laying mammals such as Ornithorhynchus (platypus) are oviparous ⇒ (4) has an exception.
As per NCERT, Chondrichthyes are marine animals with a cartilaginous endoskeleton ⇒ (3) holds without exception.
Answer: (3)