In One Line What Is Link Building

Hi!
My Name Is Mahesh Gangurde
I Am Student Of Digital Marketing
Can Anybody Tell Me What Is SEO In One Single Line
My Website Name Is http://www.webdigital4u.in

SEO is a series of technical marketing techniques used to improve a web site's rankings in search engines like Google. Identifying good keywords, developing quality links, code validation and content markup are central to SEO.

SEO is the process which helps out to increase the visibility of the website in SERP's results.

SEO is the process of making your websites as search engine friendly, increases the traffic and rank to your website.