Domain is either you or your company's ID in the Internet, when you apply to connect to Internet, they will give you protocol number. Every device connected to Internet has an IP number.
It's crucial to use alt tag and to make sure search engines know what you are talking about.
If there is no alt tag, search engine doesn't understand anything from the image.
You should not have too much external links on your website.
Other wise this will affects your website negatively.
Meta description section character number of site is 0 character.
This part is explanation part which is seen in search engines.