2. which describes the characteristics of a depressant? a a drug that slows nervous system activity and relaxes tension b a drug that produces feelings of well-being and high energy c a drug that makes one hyperactive d a drug that causes paranoia

A

Explanation:

I think that the answer is A, since depressants are used to lower neurotransmission levels, which is to depress or reduce arousal or stimulation.

A a drug that slows nervous system activity and relaxes tension

Explanation:  

Depressants are chemical substances that directly affect the Central Nervous System, causing a slow or low brain activity and are accompanied by feelings of relaxation, like when drinking alcohol, a legal depressant , or benzodiazepines, that are commonly more known as sleeping pills, they cause drowsiness, lowering levels of blood pressure, and other drugs like barbiturates, often have a big sedative effect.

Many different kinds of depressants include also  substances coming from Opioids, for lessening pain, or Cannabis, commonly and recently studied for its  Effects of Central Nervous System

Since the Central nervous system depressants increase the production of the neurotransmitter GABA, the sensations often associated to the brain will be opposed to the other antagonic processes : stimulating drugs.