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.

Q: Question: Where on earth do bacteria live? Answer: all environments

A: All environments on earth do bacteria live.
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Q: Question: Early in the development of a human fetus, the skeleton is made entirely of what? Answer: cartilage

A: Early in the development of a human fetus, the skeleton is made entirely of cartilage.
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Q: Question: The concentration of the hydrogen ion in a solution can be calculated when what is known? Answer: ph

A:
The concentration of the hydrogen ion in a solution can be calculated when the ph is known.
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