Which phase of the human sexual response cycle is not affected by a sexual dysfunction?

Many people who are depressed __________.

A. show very little REM sleep, instead spending large amounts of time in the deeper stages of sleep (3 and 4) B. do not enter REM sleep until much later in the night than normal, and have less REM sleep throughout the night than normal C. enter REM sleep earlier than normal and have more REM sleep early in the night D. enter REM sleep at a normal time but have very slow and mild rapid eye movements, and have less overall time in REM sleep than normal

Attention-deficit/hyperactivity disorder has been linked to irregularities in the way which of the following neurotransmitters operates in the brain?

a. dopamine b. serotonin c. acetylcholine d. GABA