I dont understand the unordered lists

Answer 1

Means "unnumbered", the order rest unchanged ;)

Answer 2

@Michael Isac Girardi:

I don't think so, because of the html tag in question, he means <ul> ( vs <ol> ) html tag ;)

Answer 3

Perhaps you intend "unsorted" list? If yes think about a short text composed by a few lines.. you can not sort it otherwise you may lose its meaning..

Answer 4

thank you visph, you are right! sorry for my answer..