Density is defined as how thick or thin you want your hair to be. The standard and most popular choice is 130% which is Medium Density. You can see examples of the density - Click Here.
Google's Gmail Web-based email service runs on the Internet Message Access Protocol system, but it also offers Post Office Protocol mail server access.
1 Simple Mail Transport Protocol is used on the internet, it is not a transport layer protocol but is an application layer protocol.  HTTP - Hypertext Transfer Protocol is used to transport HTML pages from web servers to web browsers. The protocol used to communicate between web servers and web browser software clients.