Louis Pasteur became famous in the field of bio-chemistry in 1848. He solved a mystery that several scientists had been trying to decode. Through his discovery, he demonstrated the unusual effect created by light when it was made to pass through a solution of dissolved tartaric acid. Tartaric acid is a combination of many acids. Pasteur concluded that the unusual effect of light was a result of this combination present in tartaric acid.
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Your instructor asks you to write an essay about a well-known scientist. You have chosen to write about Louis Pasteur. In your research, you come across the passage above, which is taken from an encyclopedia. What is the best way to classify this passage?
A.
a primary source
B.
a secondary source
C.
a work of fiction
D.
a quote