Whenever a link with port 80 is made, I just read these client demands are addressed by child servers(just in case of prefork MPM) or server thread(in worker MPM) although not by master server(the apache process that's began first through the root user and which accounts for forking new child). But exactly how, these child servers and server threads run as non-fortunate customers and thus just how can they access the fortunate port 80 which only works through the 'master server'. Please throw some light about this. I have not seen any explanation anywhere.

You simply need rights to start listening on the fortunate port. If the operation is began as root, it can bind() on port 80, after which drop rights. It'll no more be root, but as lengthy as it doesn't close the filedescriptor that learns port 80, it'll still have the ability to accept new connections on port 80.

To fork new processes, you'll need no special privileges....