Answer:
the conditioned response (CR).
Explanation:
Since Youri had leukemia and had undergone various chemotherapy that made him nauseous every time he goes. And, its been a year of his treatment that now even the waiting makes him feel nauseous because he feels that again he will have to undergo chemotherapy. This nauseous feeling from chemotherapy is referred to as the conditioned response.
The term conditioned response has been used in a classical conditioning experiment by Ivan Pavlov, which refers to reflexive behavior or the learned response concerning a conditioned stimulus.
