They are part of the human brain.
I believe the answer is street drugs and over-the -counter medications.
Streets drugs is dangerous in general because the majority of them are created without proper research and acknowledgement from trusted establishments.
Even though most of the over-the-counter drugs are approved by FDA, they tend to cause problem because many of its users use the drugs to treat the wrong sickness or purposely use it as a form of recreational drugs.
Combining two or more segments of the industry to deliver the best care, at the most cost-effective rate, in the best setting should refer to D) integrated delivery system (IDS).
