Answer:
HCI creates an acidic environment, which promotes the process of pepsin.
When that happens, pepsin is maximally active and works on a fully digestion of the presented protein.
On the other hand HCI prevents the activeness of the amylase, thereby only a small part of starch is digested.
Step-by-step explanation:
The physiological significance of these effects are: salivary glands found in the mouth which has a neutral pH environment segregates amylase, meanwhile pepsinogen becomes pepsin thanks to the compatibility with this environment.
While pepsin is widely active at a lower pH inside the stomach, amylase activity, on the other hand decreases at lower pH environment.