Final answer:
Carbohydrate digestion begins in the mouth with the enzyme salivary amylase but stops in the stomach due to the acidic environment that inactivates the enzyme.
Step-by-step explanation:
The statement that carbohydrates start to breakdown in the mouth and stop in the stomach due to low pH is True. The digestion of carbohydrates begins with the enzyme salivary amylase, also known as ptyalin, which is present in saliva. This enzyme initiates the breakdown of starches into maltose and other simple sugars in the mouth. However, the process halts in the stomach because the acidic environment there rapidly inactivates salivary amylase, and there are no enzymes in the gastric secretions that continue the digestion of carbohydrates.