Amendments to federal drug laws in 1965 changed the pattern of amphetamine abuse in the following way: .

D. amphetamines became available from illegal laboratories rather than legitimate pharmacies

Explanation:

Due to the amendments to federal drug laws known as Drug Abuse Control Amendment of 1965, amphetamine became available from illegal laboratories rather than legitimate pharmacies. Prior to the amendment drugs like barbiturate, amphetamine and lysergic acid diethylamide (LSD) could easy be gotten from pharmacies but the amendment restricted the availability of such drugs. The amendment was as a result of increase in drug abuse among the American population.

answer; biological;

answer; does not include a reference to the audience;