You are presented with the question "Sharks have as skeleton that contains" and the following answer choices: 
- elastin
 - Epidermis
 - calcium
 - fur and fat
 - marrow
 - strength
 - all matter
 - collagen

Now knowing that cartilage is a tough tissue that contains a protein called collagen and sharks have a cartilage skeleton, choose the best answer.


 

        collagen 