Detailed Instructions: In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.
Q: Question: When food enters the stomach after a period of fasting, a drop in what initiates the conversion of pepsinogen to pepsin? Answer: ph
A:
Ph food enters the stomach after a period of fasting, a drop in what initiates the conversion of pepsinogen to pepsin.