<head> and <html> tag mandatory for being valid HTML-file?
In one of the HTML challenge question it was asked whether which tags are needed for being a valid HTML file. The accepted answers were <html> and <head>.
I think this is not quite correct. Because since HTML5 it is allowed to omit the <head> and <html> (and also the <body>) tags.
Sources:
https://www.w3schools.com/tags/tag_head.asp
http://stackoverflow.com/questions/5641997/is-it-necessary-to-write-head-body-and-html-tags
