What law do the justice system have that protect juveniles from being tried as an adult?

What law do the justice system have that protect juveniles from being tried as an adult?
What type of crimes must a juvenile commit before being tried as an adult.I believe violent crime such as murder, assaults with a deadly weapon that result in deaf upon an innocent person, the juvenile should be charge as an adult.
I feel juveniles who are tried as adults, should be offered different types of treatment such as anger management or mental health as needed, to address the violent behavior.
Juvenile who have not completed schooling should be required to completed, a GED program along with the necessary treatment they need before release into the communities in which they live.
Juvenile should be release into stable home environment, I believe this will help juvenile offender, restart there live more productively and will eliminated the urges to reoffend.