In pavlov's experiments on classical conditioning, prior to associating the sound of the bell with the food, the dog's salivation in response to the food was the

They were conditioned to salivate in response to the sound of a bell.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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