I believe the answer is: Recidivism
Recidivism refers to The tendency for criminal to repeat the offense that made them convicted in the first place.
Many experts believe This happen because the prison system in united states do not add enough educational value for the inmates to change their behaviors/way of thinking.
This depends on who's providing the theory but the best answer would be 8-10 years old. Of course, children start walking alone often even earlier, especially in societies where the raising children is not taken seriously or the children have high autonomy over their actions.
Because children are not very skilled at expressing themselves.
Increasing because western Europe is a world leader in environmental issues and Europe is very polluted so its most likely increasing
