Final answer:
The dog's salivation to the sound of the bell alone is called the conditioned response (CR).
Step-by-step explanation:
The dog's salivation to the sound of the bell alone is called the conditioned response (CR). This is because the dog has learned to associate the sound of the bell with the arrival of food, which causes the salivation response. In this case, the sound of the bell has become the conditioned stimulus (CS), and the dog's salivation is the conditioned response.