In classical conditioning a stimulus is any event or situation that

evokes a response.        

Explanation:

Classical conditioning: The term classical conditioning is proposed by a psychologist named Ivan Pavlov after experimenting with dogs. According to him, classical conditioning is described as the behavior that is being learned through a repetitive association or exposure between the stimulus and the response.

Stimulus: Here, in the process of classical conditioning the stimulus works as an event or situation that evokes or leads to a specific response. The response to any stimulus will depend on the content of the stimulus. Every stimulus will have a different response.

In the question above, in classical conditioning, a stimulus is any event or situation that evokes a response.

facts: the 14th amendment

the 14th amendment addresses citizenship rights and equal protection of the laws.

the 14th amendment was intended to protect the rights of former slaves after the american civil war.

the 14th amendment was approved by congress in june of 1866 and ratified by the states on july 9, 1868.

the 14th amendment establishes that all persons born in the united states are citizens and are guaranteed all the rights of citizenship.

the 14th amendment establishes that the law protects all citizens equally.

in this case the passage of the 14th amendment   that was violated was the last part in which it states that there is equal protection of the law.