your=belonging to you you're= I am, you are, we are 'strayian! Yours does not take an apostrophe! Its=belonging to it it's=it is
The apostrophe is used only to indicate possession or a missing letter, usually the "i".
So, Atomou's hair (ie the hair that belongs to Atomou) is missing! If the name ends in "s" (Mr Waters) then only an apostrophe is needed after the "s" : Mr Waters' wife is beautiful. There is no need for a further "s" as one sees quite often these days: eg, it is WRONG, WRONG, and WRONG to write "Mr Waters's wife..."
