Check My Answers (Prepositions)

My task: fill in gaps with prepositions where it's necessary. Please check my answer and help with where I don't know
The advertising agency is a mediator between the advertisers (manufacturers and distributors) and the mass media (print and broadcast). To be successful, the agency must serve both interests.
All agencies have certain client preferences. Some agencies deal with food and beverages, electronics, clothing and fashion; others with travel, drugs or cosmetics. ? this kind ? specialization, agencies are able to become closely acquainted with the particular facets of their client pricing, marketing and manufacturing problems. Some agencies prefer print as their basic medium, while others concentrate on television and radio. A large advertising agency is a complex structure. A number of large agencies have review boards composed of major executives who play devil's advocate ? any planned campaign ? it goes ? the client.