AP BIO !!! That is the hardest AP class.
Answer:
an automatic response established by training to an ordinarily neutral stimulus.
Explanation:
For example, the smell of food is an unconditioned stimulus, a feeling of hunger in response to the smell is an unconditioned response, and the sound of a whistle when you smell the food is the conditioned stimulus. At this point, the response becomes known as the conditioned response.
D. Boycott is your answer
The other 3 are all types of people, a group of people, while boycott is an action that is used by people
hope this helps
