A. Heredity, unhealthy behaviors, and the environment. Heredity is passed down from parents or even family before your parents leading to unchangeable diseases, for example, severe acne or a heart attack at an early age. Unhealthy behaviors like eat junk food instead of healthy foods will lead to high blood pressure, heart attacks, or even strokes. The environment on the other hand CAN be helped just like unhealthy behaviors. For example, high density pollution in a city will cause lung cancer and difficulty breathing and asthma. I hope this information helped you guys understand the question better! :)