YES! In shared hosting, the resources you are allotted are dedicated to you. No doubt you share the server with others; you can't sell out any portion of your account to a third party. It is suitable for low-traffic websites and small businesses but it doesn't give you complete control over your server environment.

Shared Hosting allows multiple users/websites/accounts to be hosted on a single web server. Dedicated hosting, in its turn, is a single server solely devoted to one user. In a nutshell, the difference between a Shared and a Dedicated hosting server is like an apartment in a block of flats and a cottage house.

YES, you can, as many as you want to.

Shared hosting works best for new sites and small sites that don't see much traffic. That allows them to remain within the limits established by many users drawing from a shared server's finite resources and allows sites room to grow – to an extent.