Question

Chondrichthyes differs from osteichthyes in presence of

• A. Cartilagenous vertebral column
• B. Operculum
• C. Air bladder
• D. Both A and C

Answer 1

The correct option is A Cartilagenous vertebral column

1) Cartilaginous fishes are also referred to as Elasmobranchii.

• Its endoskeleton is primarily made of cartilage.
  
• Its exoskeleton is made of placoid scales.
  
• They do not have an operculum and an air bladder.
  

2) Bony fishes are referred to as Teleostomi.

• Its endoskeleton is entirely made of bone.
• Its exoskeleton is made up of cycloids scales.
  
• They have an operculum on either side of their gills and also have an air bladder
  
• So, the correct answer is 'Cartilaginous vertebral column'.