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.

Ex Input:
Question: The concentration of hydrogen ions in a solution is called? Answer: acidity

Ex Output:
The concentration of hydrogen ions in a solution is called acidity.


Ex Input:
Question: Why did people stop adding lead to gasoline? Answer: environmental pollution

Ex Output:
People stopped adding lead to gasoline because of environmental pollution.


Ex Input:
Question: What force is caused by microscopic bumps, lumps, and imperfections colliding? Answer: friction

Ex Output:

Friction force is caused by microscopic bumps, lumps, and imperfections colliding.