Answer:
risk behaviour or risky behaviour is simply behaviour that runs the risk of the person and/or those around them being hurt or damaged physically, socially or emotionally.
Teenagers investigating it? It depends on what you mean by ‘investigating’. Investigating does not have to mean trying it out. Trying out certain drugs is too risky. On the other hand, trying out mountain bike tricks may be well worthwhile if they develop their manoeuvres in a staged way, starting from the easiest and safest and working up the scale as they master the easier stages one by one.