How are bony fish better adapted to a swimming way of life than cartilaginpus fish?

Cartilaginous fishes have an internal skeleton made of cartilage and their skin is covered with placoid scales.

While, The bony skeleton of bony fishes is harder and heavier than cartilage. Bony fishes have either lungs or a swim bladder and hard, thin scales.

Does this help?

Cartilaginous fishes have an internal skeleton made of cartilage and their skin is covered with placoid scales.

The bony skeleton of bony fishes is harder and heavier than cartilage. Bony fishes have either lungs or a swim bladder and hard, thin scales.

b

explanation:

not sure if this what   you'r looking for would be percent composition