Final answer:
Once a conditioned behavior is extinguished, it can sometimes reappear due to spontaneous recovery.
Step-by-step explanation:
Once a conditioned behavior is extinguished, it can sometimes reappear. This phenomenon is called spontaneous recovery. Spontaneous recovery is the return of a previously extinguished conditioned response following a rest period. It occurs because the original association between the conditioned stimulus and the unconditioned stimulus is still present in the organism's memory, even though the behavior was temporarily suppressed.