Diagram is showing chemical structure of Morphine, which is a natural opiate like codeine. Morphine is a strong analgesic, also has sedative & calming effect. It depresses respiratory centre, BP, heart beat. Constipation is a prominant feature of morphine action. How many ester linkages are present in a morphine moleucle ?
A. 2
B. 3
C. 4
D. Absent