One of the difficulties in conducting studies of the specific effects of methamphetamine is that
A)its use is very rare.
B)many users have also used other substances.
C)individuals who use it are particularly likely to also use crack.
D)most users live in rural areas.

Question

Quizplus · Accepted Answer

Methamphetamine users often use multiple substances, making it difficult to isolate the specific effects of methamphetamine.

One of the Difficulties in Conducting Studies of the Specific