Final answer:
An event or object in the environment that an organism responds to is known as a stimulus. A stimulus can be neutral initially and become conditioned when paired with an unconditioned stimulus, resulting in a learned reaction.
Step-by-step explanation:
Any event or object in the environment to which an organism responds is a b. stimulus. A stimulus is anything that can elicit a response from an organism, such as light, sound, or temperature change. In the context of conditioning, a neutral stimulus refers to a stimulus that does not initially trigger a response.
In classical conditioning, a neutral stimulus can become a conditioned stimulus when it is repeatedly paired with an unconditioned stimulus that elicits an unconditioned response. For example, in Pavlov's experiments, the ringing of a bell (neutral stimulus) became a conditioned stimulus after being paired with the presentation of food (an unconditioned stimulus) that naturally caused dogs to salivate (unconditioned response).
In another example, the process of stimulus discrimination allows an organism to distinguish between similar stimuli and respond only to the one that is conditioned. This is seen when Pavlov's dogs did not salivate to sounds other than the bell that was associated with food.