The somatic nervous system I think
Yes it’s gross and it stank
Gonorrhea can be cured. Aids can not be cured but you gave be follow a strict treatment.
The item from this list which isn't considered a stimulant would be alcohol - a. It is considered to be a depressant. All the other items - nicotine, caffeine, and cocaine have stimulating effects which are known to their useres, while alcohol doesn't have an stimulating effect generally.