Ahad: This is a Hadeeth which has only one chain of narrators. so... If Any of the narrator is found to have a bad memory etc... The Hadeeth ain't accepted.
Mutawatir: This is a hadeeth narrated by many, thus having many chains of narrators. (Like Last Sermon) So its inconceivable that many people with agree upon a lie (fake/fabricated Hadeeth). thus the hadeeth is regarded authentic...
Ahan.
Thanks gal for the help
Plus thanks again for bringing this thingy in my knowledge.