What is a VPN (Virtual Private Network) used for in

Ctrl + S shortcut key is used for:

Which port number is commonly used by the HTTPS protocol for secure web communication?

What is the fourth layer in the OSI model? 

Interpolation is made possible by a principle called

An E-mail address is composed of :

The address used to uniquely locate a webpage on the Internet is called:

Which device connects multiple networks and forwards packets?

Which is not a storage device?

Which device is used to convert digital signals to analog signals?

Which CPU internal memory is the absolute fastest?