Answer:
The correct answer is "pepsin".
Explanation:
Pepsin is an enzyme that catalyzes the hydrolysis of proteins, breaking it down into its subunits called amino acids. Pepsin is an important component of the gastric juice because it contributes largely to proteins digestion. In this case, James is having trouble to digest lean steaks and other protein-rich foods. This problem indicates that James is likely lacking the enzyme pepsin.
