To start your essay, consider the following example of classical conditioning:
When Antonio was seven years old, he got a very bad case of the flu (UR) and ended up being hospitalized(US). Although he recovered without any complications, he notices that he begins to feel sick (CR) to his stomach any time he passes by or has to visit the hospital (CS) where he was previously treated.
In your own words, explain why this is an example of classical conditioning. Be sure to define classical conditioning and identify the US, UR, CR, and CS in this scenario as appropriate.

