Final answer:
Using exaggerated pictures of girls and boys with specific features and gradually reducing these features is an example of stereotyping.
Step-by-step explanation:
Using exaggerated pictures of girls and boys with specific features (girls with long hair and dresses, boys with pants and short hair) and then gradually reducing these exaggerated features is an example of stereotyping. Stereotyping involves overgeneralizing about the attitudes, traits, or behavior patterns of women or men based on societal expectations. In this case, the teacher used stereotypes to help Bob discriminate between boys and girls.