Fact 1: Cartilage is a tough tissue that contains a protein called collagen.

Fact 2: Sharks have a cartilage skeleton.

Given the two facts above, answer the question "Sharks have as skeleton that contains" with the following options: 
- elastin
 - Epidermis
 - calcium
 - fur and fat
 - marrow
 - strength
 - all matter
 - collagen


 

        collagen 