GMAT Sentence Correction (SC) | Re: Phlogiston

Until Antoine Lavoisier proved otherwise in the eighteenth century, many scientists had believed that combustion released phlogiston, an imaginary substance whose properties were not fully understood

.a) many scientistshad believed that combustion released phlogiston, an imaginary substance whose properties were not fully understood
straight forward A. correct.


b) many scientists believed that phlogiston was an imaginary substance released by combustion and its properties were not fully understood
passive
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