Identifying unconditioned stimulus, etc.

Unconditioned responses are reflexes (e.g., salivation, pupil constriction, sneeze). Salivation can be elicited by food, for example. Pupil constriction could be elicited by shining a light in the eye. We come biologically prepared to emit these reflexes (I.e., no learning required). These, or other reflexes could come under the control of a previously neutral stimulus. Pavlov noticed that metronomes (or bells) which do not generally elicit saliva, began to do so when they were repeatedly paired with the stimulus that naturally elicited the response.

Feeling stupid (i.e., saying to oneself, "I feel stupid" about school is not a reflex. It is evoked behavior that has been learned and has come under operant control of things at school. There could also be some examples of reflex behavior at school. They would just first need to be identified in the example.