Answer:
The correct answer would be "yes, acidic environment decreases or deactivates the amylase enzyme".
Amylase refers to the class of enzymes which are involved in the hydrolysis of sugars (polysaccharides).
For example, salivary amylase and pancreatic amylase hydrolyze the starch into di and trisaccharides.
In addition, the amylase present in the human physiology (alpha amylase) has the optimum pH of 6.7-7.0 and thus, this amylase would get deactivated in acidic or low pH conditions.
This is why the pH of the intestine is slightly basic which complements the functioning of the pancreatic amylase.
The acidic medium can cause the denaturation of the enzyme and thus, results in the deactivation of the enzyme.