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: Question: Which is an example of a renewable energy resource? Answer: Biomass
Example solution: Biomass is an example of a renewable energy resource.
Example explanation: The output clearly summarizes the question and answer and hence is correct

Problem: Question: When gas pressure-forces are used to move an object the work is done on the object by? Answer: expanding gas

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Solution: Expanding gas gas pressure-forces are used to move an object the work is done on the object by.