You will be given a definition of a task first, then some input of the task.
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.

Question: Which observation demonstrates that light waves travel much faster than sound waves? Answer: An exploding firework is seen before it is heard.
Output:
An exploding firework is seen before it is heard observation demonstrates that light waves travel much faster than sound waves.