Diseases caused by waterborne parasites constitute a major global health problem. In particular, parasitic diseases affect the world's poorest populations and represent a huge barrier to improving human health and well-being. This year's Nobel Laureates have developed therapies that have revolutionized the treatment of some of the most devastating parasitic diseases. William C. Campbell and Satoshi Ōmura discovered a new drug, Avermectin, the derivatives of which have radically lowered the incidence of River Blindness and Lymphatic Filariasis, as well as showing efficacy against an expanding number of other parasitic diseases.
a. Circle all the chiral centers in avermectin below.
b. How many chiral centers did you find? ______
c. Based on the chiral centers found, how many stereoisomers are POSSIBLE for avermectin? ______