Sociologists have been carrying (1) ... research into the social pressures of being a teenager. Many adolescents are unhappy at school because they find it difficult to make friends. This stress can bring on illness or result (2) ... poor grades. They may also worry about their appearance and often feel under enormous pressure to dress, talk and behave the same as others. This phenomenon is called peer pressure, and it is very common in today's society. Advertising contributes a lot (3) ... the social pressures teenagers feel. Advertisers know how important it is to feel that you belong (4) ... a group when you are in your teens, so they try to persuade teenagers that certain products will make them popular (5) ... their classmates.