six risk behaviors that account for most of the death and disability among young people under 24 are:
first of all use of Tobacco, these days teenager use too much. Then unhealthy dietary behaviors, teenagers mostly eat fast food which is not healthy and causes problems.
Other risk behaviors are inadequate physical activity. too much use of Alcohol and other drugs, sexual behaviors that may result in fatal diseases like HIV infection and finally behaviors that contribute to unintentional injuries and violence.