Is the study of how health events affect communities--where, when, why, and how health events occur in the context of a well-defined population.

A32-year-old woman presents for a routine gynecological exam. she has been married for 5 years and plans to start a family with her husband in the near future. her first menstrual period was at the age of 11. she is in a 28/4 cycle with no irregularities or discomfort. at age 18, she had an induced abortion and has used oral contraceptives since then. in the recto-vaginal exam, you palpate a mass on the left side. an ultrasound confirms a complex cystic tumor 6cm in diameter on the left ovary. there is no free fluid in the pelvis. there is no family history of any malignant tumors. what is your therapeutic approach?

Ab+cd-> ad+bc is what kind of reaction

What is one way that vance might have been able to prevent this injury?