Final answer:
The drug cross-dependent with Seconal, a barbiturate, is alcohol, as both are central nervous system depressants affecting GABA neurotransmission.
Step-by-step explanation:
Cross-dependency refers to the ability of one drug to partially substitute or alleviate the withdrawal symptoms of another drug in the same class. In this context, Seconal, a barbiturate, may exhibit cross-dependency with another substance that shares similar effects or actions on the central nervous system.
The correct answer is:d) alcohol
Alcohol, a central nervous system depressant, shares some pharmacological properties with barbiturates like Seconal. Both substances affect GABA receptors, resulting in sedative effects. Due to their similarities in impacting the central nervous system, there might be some degree of cross-dependency between Seconal and alcohol. This means that in some cases, the use of one substance might alleviate withdrawal symptoms or cravings associated with the other within the same class of drugs, although this interaction can vary based on individual factors and the specific substances involved.