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.
The Simple Mail Transfer Protocol (SMTP) is used to transfer electronic mail from one user to another. This task is done by means of email client software (User Agents) the user is using. User Agents help the user to type and format the email and store it until internet is available.