Tryptophan depletion has been used to a) lower serotonin ...

[nautica902]

Tryptophan depletion has been used to
 
  a) lower serotonin levels.
  b) examine dopamine receptors.
  c) deplete norepinephrine levels.
  d) raise sensitivity for serotonin.

Question 2

What do alcohol, tranquilizing drugs, amphetamines, and heroin have
  in common?
 
  a) Overdose can result in death.
   b) They cause delusional thinking.
   c) They can cause long-term coma.
   d) The abuser experiences hallucinations.

[trampas]

Answer to Question 1

a

Answer to Question 2

a