What is operant conditioning? how does it differ from classical conditioning?

Operant conditioning is reinforcement, classical conditioning relies more on association between stimuli and responses. A second distinction is that much of operant conditioning is based on voluntary behavior, while classical conditioning often involves involuntary reflexive behavior.

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.