Children have developed the appearance–reality distinction by the age of

Which of the following statements is true concerning classification systems for mental disorders?

A) It is far more important that they be reliable than it is for them to be valid. B) Although they assist scientists who are researching disorders, they inhibit our ability to communicate about abnormal behavior in a precise way. C) Classification systems make it more difficult to gather statistics on the incidence and prevalence of disorders. D) Classification systems meet the needs of medical insurance companies who need diagnoses in order to authorize payment of claims.

Which is considered to be the most prevalent excitatory neurotransmitter in the mammalian CNS?

A) GABA B) glutamate C) dopamine D) acetylcholine E) none of the above