“Their assimilation and nativism created a lot of discrimination against immigrants.” (explain what this means in easy words and tell me if it makes sense)

How can behavioral science be applied in improving public health? a.by tracking a disease to determine its sourceb.by creating promotions that improve health habitscboth by tracking a disease to determine its source and by creating promotions that improve health habitsd.neither by tracking a disease to determine its source or by creating promotions that improve health habits