Teenage boys, regardless of race, are more likely to die from gunshot wounds than from all natural causes combined. By the time the average American child leaves primary school, he or she will witness 8,000 murders and more than 100,000 acts of violence on television.  Youth are becoming involved in violence at an alarming rate. In fact, the young arrest rate for murder doubled, from 6 arrests per 100,000 youth aged from 10 to 17 to over 12 per 100,000.  For the many youth who have not been directly exposed to violence in their own communities, the entertainment media (television, movies, music and video games) provides many opportunities for children to see and hear violent exchanges. Research shows that there are about 5~6 violent acts per hour on prime time and 20~25 violent acts on Saturday morning  children's programming. In its report, the American Psychological Association (APA) reported that viewing violence on television hurts children in many ways. In particular, the APA  concludes that children may become less sensitive to the pain and suffering of others, be more  fearful of the world around them, be more likely to behave in aggressive or harmful ways to- ward others, and gradually accept violence as a way to solve problems. Another form of violence involving youth is physical punishment in the schools. This form of discipline   still remains legally supported in 23 nations in America. The Office for Civil Rights in the Department of Education reported that 555,000 students were physically punished in the schools during this school year. Although such punishment has been regarded as an effective method of discipline by those who apply it, the findings are obvious that physical punishment does not work and that children who are victims of physical punishment are subject to potential long-term physical and emotional damage. According to the passage, the American teenage boys' lives are most threatened by  _  .
gun murders natural diseases TV violence physical punishment