Answer:
1. CS and UCS 2. closely enough in time to be perceived as related
Step-by-step explanation:
Classical conditioning is a process of learning through association in which two separate stimuli are paired/linked together which produces a new learned response.
For example:
Food: Is an unconditioned stimulus that produces an unconditioned response of salivation in dogs.
A bell: Is a previously neutral stimulus that when paired with the unconditioned stimulus it ends up becoming a conditioned stimulus.
In conclusion, the correct answer is: 1. CS and UCS 2. closely enough in time to be perceived as related.