Answer:
(A) Pepsin
Step-by-step explanation:
From the graph it is clear that pepsin is the only enzyme which works in highly acidic condintion in the digestive system.
- less than 7 the liquid is acidic
- above 7 the liquid is basic
- at 7 the liquid is neutral
It has an optimum pH of about 1.5 at which its activity level is 8.5 as shown in graph.