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.

Example Input: Question: What is the amount of product that may be produced by a reaction under specified conditions called? Answer: theoretical yield
Example Output: The amount of product that may be produced by a reaction under specified conditions is called theoretical yield.

Example Input: Question: When do weather balloons return to earth? Answer: when it bursts
Example Output: When it bursts do weather balloons return to earth.

Example Input: Question: What is the phenomenon in which light and sound waves become circular at the point source of a barrier? Answer: diffraction
Example Output:
Diffraction is the phenomenon in which light and sound waves become circular at the point source of a barrier.