The use of heroin under sterile conditions has been associated with lesions and/or cell death in the

Mixing acquisition and extinction trials in operant conditioning is called

(a) acquisition (b) extinction (c) partial reinforcement (d) spontaneous recovery (e) discrimination

Neonatal mortality has ______ across ethnic groups in the United States since 1980

a. increased sharply b. dropped steeply c. remained the same d. decreased little