You are presented with the question "what contributes to meat toughness?" and the following answer choices: 
- digestion
 - cartilage
 - layers of fat
 - h2o
 - exercise
 - Animal fur
 - the skin
 - steak

Now knowing that cartilage is a tough tissue that contains a protein called collagen and collagen contributes to meat toughness, choose the best answer.


 

  cartilage       