Why are sharks cartilaginous fish?

Cartilaginous fishes:

1. Cartilaginous fishes are also referred to as Chondrichthyes.
2. These are jawed vertebrates that have skeletons made up of cartilage.
3. Cartilaginous fishes possess paired fins and nostrils.
4. These are mostly marine fishes and have ventrally located mouths.
5. Their cartilaginous skeletons have a deposition of calcium over them that provides them strength.
6. Sharks show all of these characteristics and thus, they are placed under cartilaginous fishes.
7. This group consists of fishes like sharks, rays, skates, Chimaeras, etc.