Two Internet Connections To One Computer

#1
Is it possible to have two internet connections for one desktop? I know many of you may say yes it is which I know but the two connection would be wired connections, which I would like both to be connected to my desktop, and I can then choose which connection to connect to and switch whenever the requirement. If any routers are required please provide details for that too.
 
#2
Yes you can use two different connections with one computer. You can use a wired and a mobile connection and also use two mobile connections as well as two wired connections.
 
#3
Yes you can use two different broadband connections with one computer, just switch the connection when you want to use the other one.