layer 7 of the osi model, which interacts with application programs that incorporate a communication component such as your internet browser and email  ex) http, ftp, smtp
osi model layer that interacts with application programs that incorporate a communication component such as your internet browser and mail. - service advertisement. - application services.
'marked clauses'- manipulated sentences,unusual, don't always follow svo want to highlight something what is considered most important what is assumed the audience already know