Final answer:
The UCS is the red minivan that rear-ended Bob, and the UCR is Bob's physical reaction. The red minivan becomes the CS that elicits the CR.
Step-by-step explanation:
In this scenario, the unconditioned stimulus (UCS) is the red minivan that rear-ended Bob at a red light, causing an automatic response. The unconditioned response (UCR) is Bob's automatic physical reaction of tensing up and getting goosebumps. At first, the red minivan is a neutral stimulus (NS), meaning it does not produce a response. However, after the incident, the red minivan becomes the conditioned stimulus (CS) that elicits the conditioned response (CR) of Bob tensing up and getting goosebumps.