GMAT Sentence Correction Modifier || GMAT Sentence Correction strategy || A substance derived from

#sentencecorrection #sentencecorrectiontricks #sentencecorrectionrules A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients, is cultivated in China as part of a program to integrate traditional herbal medicine into a contemporary system of health care.  A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients,  A derivative, which has proved useful in decreasing mortality among young leukemia patients, of the Madagascar periwinkle,  A Madagascar periwinkle derivative, which has proved useful in decreasing mortality among young leukemia patients,  The Madagascar periwinkle has a derivative which has proved useful in decreasing mortality among young leukemia patients, that  The Madagascar periwinkle, a derivative of which has proved useful in decreasing mortality among young leukemia patients, #howt