Sharks use their gills to filter oxygen from the water. They are a special type of fish known as "elasmobranchs", which translates into fish made of cartilaginous tissues—the clear gristly stuff that your ears and nose tip are made of. This category also includes rays, sawfish, and skates. Their cartilaginous skeletons are much lighter than true bone and their large livers are full of low-density oils, both helping them to be buoyant.
Even though sharks don't have bones, they still can fossilize. As most sharks age, they deposit calcium salts in their skeletal cartilage to strengthen it. The dried jaws of a shark appear and feel heavy and solid; much like bone. These same minerals allow most shark skeletal systems to fossilize quite nicely. The teeth have enamel so they show up in the fossil record too.
The following,... and uh I don't have a journal ;->
Step-by-step explanation:
You and your 10 friends each have 121 books that you will be bringing to a Best Book Barrage book exchange. Once everyone arrives you count a total of books. Assuming everyone brings the same amount of books how many people came to the exchange?
