Q1. a unique string of numbers separated by periods that knows when each computer using the Internet Protocol then they communicate over a network.
Q2. A domain name is the part of a network address that identifies it as belonging to a particular domain. It relates to a IP address by both being a part of the place where information sent over the internet is received.
Q3. HTML stands for Hypertext Markup Language
Q4. The default page in a website is named the index.html page