Question

Which of following characteristic features always holds true for corresponding group of animals?

• A. $3$-chambered heart with one incompletely divided ventricle --- Reptilia
• B. Cartilaginous endoskeleton --- Chondrichthyes
• C. Viviparous --- Mammalia
• D. Possess a mouth with an upper and lower jaw --- Chordata

Answer 1

Answer: (B)

Cartilaginous endoskeleton --- Chondrichthyes

B. Cartilaginous skeleton-Condrichthyes

Reason: Chondrichthyes is a subclass of class Pisces which consist of cartilaginous fishes. They are jawed vertebrates and have paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone. Most common examples found in this subclass are Sharks, Rays, Skates etc. So the correct option is B.