Answer:
Caffeine is a central nervous system stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug. Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine.
Cocaine is a tropane alkaloid and stimulant drug obtained primarily from the leaves of two coca species, Erythroxylum coca and Erythroxylum novogranatense. It is most commonly used as a recreational drug and euphoriant
Amphetamine is a central nervous system stimulant that is used in the treatment of attention deficit hyperactivity disorder, narcolepsy, and obesity. Amphetamine was discovered in 1887 and exists as two enantiomers: levoamphetamine and dextroamphetamine.
The difference between drugs and medicines is pretty basic, but a lot of people often interchange them. The main thing that differentiates them are their legality and society's perception of them. Both are used for the treatment or cure of diseases, but drugs have a more stimulating and addictive effect to the body than medicine. On the other hand, medicines generally don't have such effects.
The answer to this question would be: <span>B. Receptor site
The receptor site of a neurotransmitter often only receives a specific kind of transmitter. That was because the receptor has a unique 3D structure, so different transmitter wouldn't fit into the receptor. That was similar to lock and key principles.</span>
