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: What type of light is composed of many rays having random polarization directions? Answer: unpolarized light

A: Unpolarized light type of light is composed of many rays having random polarization directions.
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Q: Question: Expansion of a gas into a vacuum is irreversible because the external pressure is measurably less than the internal pressure of the gas, and no states of what exist? Answer: equilibrium

A: Expansion of a gas into a vacuum is irreversible because the external pressure is measurably less than the internal pressure of the gas, and no states of equilibrium exist.
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Q: Question: How is most evidence gathered in science? Answer: lab experiments

A:
Lab experiments is most evidence gathered in science.
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