4d.+Cartilaginous+Fish

__**Cartilaginous Fish**__

Cartilaginous Fish are in the phyla of Chordata. All this means is that they have a backbone (vertibrate). Unlike Bony-fish, this subphyla does not have a swim bladder and its skeleton is made of cartilage. Not having a swim bladder doesn't allow them to float without moving. Also, cartilage bones make this subphyla more flexible and fast. Some known examples of Cartilaginous fish are sharks, and rays. All species in this subphyla eat by using jaws and a digestive system. They breathe by using blood vessels in gills that asorbe oxygen from the water. The cartilaginous fish's eggs are fertilized in the female, and they reproeduce sexually. The cartilaginous fish moves by using its different fins. It can live in fresh or salt water, and some if the cartilaginous fish have three layers of teeth to protect itself from predators. The cartilaginous fish have been around for more than 400 million years.