James has been having trouble digesting lean steaks and other protein-rich foods, and these foods seem to stay in his stomach longer than usual. James is likely lacking the enzyme .

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.

i think that d. wind is the answer.   i missed the question when i answered a. currents.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: