The hair-like appendages that extend from the ends of the auditory receptors are known as ________

To control for this bias in drug studies, participants are kept blind as to whether they are receiving the active drug or placebo:

a. personal b. observer c. expectancy d. placebo e. confounding

Alzheimer's disease may involve below-normal levels of the neurotransmitter ______

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