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.
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Question: Question: What is the smallest unit of time commonly based on? Answer: second

Answer: Second is the smallest unit of time commonly based on.

Question: Question: Which characteristic is shared by all cells? Answer: They need energy.

Answer: All cells share the characteristic that they need energy.

Question: Question: What do we use to keep track of electric potential energy? Answer: voltage

Answer:
We use voltage to keep track of electric potential energy.