When you are ill, some or all of your body is not functioning properly. Either your body or the environment might be the source of a disease. Internal diseases are typically passed down through the genes you inherit from your parents, which provide the blueprint for how your body will develop and function. Many chronic disorders are brought on by abnormal body system development or operation.

You should exercise for your health. Regular exercise promotes healthy bones, muscles, and weight management, as well as the prevention of some diseases and a positive view on life. Regular exercise encourages healthy digestion and restful sleep. Children who incorporate exercise into their hectic schedules are better able to handle the mental and physical demands of a full day.

Substance abuse is the use of substances (other than those that are medically prescribed for a specific ailment) in quantities that are risky or that prevent a person from going about their daily lives, including to work or school. Alcohol, marijuana, tranquilizers—pills that induce extreme fatigue or relaxation—household goods that are breathed, as well as a variety of other medicines, can all be used as substances of abuse. People of all ages, both young and elderly, abuse drugs all throughout the world.