This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Digestion and Absorption, Subject name: Physiology
[{'content': 'Salivary amylase is Inactivated by - \nSelect and explain. \nA. Enteropeptidase, B. Low pH of the stomach, C. High pH of the intestine, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Low pH of the stomach o Saliva contains amylase (salivary amylase or ptyalin), which hydrolyzes starch into disaccharide maltose and a mixture of oligosaccharides. o Its action is very short- lasting because it is inactivated by acidic gastric pH (< 3) shortly after entering the stomach. Salivary amylase optimally active at pH of around 6.9 (6.5 - 7). o It is inactive at a pH below 4.5.", 'role': 'assistant'}]