3. Tyrell was once bitten by Rover, the neighbor’s dog, and as a result he developed a strong fear of the dog. However, when he heard that Rover had to have all his teeth removed, Tyrell’s fear of the dog completely disappeared. This suggests that Tyrell’s fear response was based on an - association.

(Think: Was Tyrell’s fear based on associating Rover with the response of fear or with the possibility of being bitten?)